ISCMs are State-led however, due to their international nature global processes and dialogues are usually facilitated by intergovernmental organizations. 

These global processes are inter-State, international policy dialogues on migration at the global level, facilitated by an intergovernmental organization, and focusing either on overall migration governance at the global level (e.g. International Dialogue on Migration), on specific themes (targeted migration consultations and discussions in global bodies that have specific responsibilities over certain elements of migration through international conventions and protocols), or on the interlinkages between migration and other areas.

While they are not technically led by States, they are still inter-State consultation mechanisms on migration and are important bricks in global governance of migration. 

Among these only the International Dialogue on Migration (IDM) focuses on overall migration governance at the global level. 

Others address or specific themes or inter-linkages between migration and other areas, such as development (e.g. the now dormant UN High-level Dialogue on international migration and development was considered a global process on migration). Other forums addressing different aspects of migration include the UNHCR High Commissioner’s Dialogues on Protection Challenges; the UNODC Congress on Crime Prevention and Criminal Justice; the International Labour Conference; and the International Conference of the Red Cross and Red Crescent. These processes are global but not State-led although they are facilitated by intergovernmental organizations, mostly the United Nations system.

A number of intergovernmental organizations also initiated global consultations that focus on various aspects of migration as per their respective mandates, such as the UNHCR High Commissioner’s Dialogues on Protection Challenges, the International Labour Conference, UNODC Congress on Crime Prevention and Criminal Justice

In the early 2000s, discussions on the migration and development nexus have gained increased prominence at international level. Important globally inclusive efforts in multilateral contexts included the High Level Dialogue on migration in the General Assembly, the Global Forum on Migration and Development, and the United Nations High-level Political Forum on Sustainable Development

These global processes, along with other initiatives and dialogues developed in States a certain level of comfort in the concept of informal, non-binding dialogues and consultations. So when the time came, states felt ready for the Global Compact on Safe, Orderly and Regular Migration and the Global Compact on Refugees. Over time, RCPs and IRFs paved the way for global processes on migration and then all ISCMs together paved the way for the Global Compact for Migration.

Global processes on migration are distinct from global initiatives addressing migration. Global processes on migration are inter-State consultation mechanisms on migration at the global-level; they are ongoing forums for informal and non-binding dialogue that address a broad range of issues in regular meetings. Global initiatives addressing migration are the quasi-legal international instruments without legally binding force (“soft law”) that either address migration in all its dimensions or certain aspects of migration and their interrelations with other domains.

IGO-facilitated global processes addressing migration can either focus on all aspects of migration governance or address specific areas of migration governance or interlinkages with other domains.

I. Global processes on overall migration governance at the global level

International Dialogue on Migration (IDM)
Established 2001

IOM’s International Dialogue on Migration (IDM) of the International Organization for Migration (IOM) has held a pioneering role in bringing together since 2001 all migration stakeholders, at a global level, for free and open discussions on the opportunities and challenges which migration presents. The IDM remains the principal forum for migration policy dialogue that encompasses all areas of migration management. Rooted in IOM’s Constitution and Strategy, the IDM is open to IOM Member and Observer States, as well as all actors on migration, including intergovernmental organizations, relevant non-State actors, self-governing bodies, and migrants. The IDM provides a space to analyse current and emerging issues in migration governance and to exchange experiences, policy approaches and effective practices.

Every year, the IDM is guided by an overarching theme selected by the IOM membership though a process of informal consultations. The annual theme is elaborated during workshops and concludes at the IOM Council Sessions, bringing together migration policymakers and practitioners from around the world. 

Regional consultative processes on migration and interregional forums on migration contribute to the IDM discussions on particular themes related to regional migration governance.
https://www.iom.int/idm

II. Global Processes focusing on specific themes

Global Processes addressing issues related to refugees and internally displaced people 
UNHCR High Commissioner’s Dialogues on Protection Challenges

Established 2007
The Dialogues on Protection Challenges facilitates a lively and informal discussion on new or emerging global protection issues, protection challenges related to UNHCR's mandate and work, with the aim to identify ways to strengthen the protection of people of concern to the refugee agency. The Dialogue on Protection Challenges is not structured to elicit formal or agreed outcomes, but rather provides a unique forum for a free and open exchange of views between states, non-governmental and intergovernmental organizations, the academic and research community and other stakeholders. At the close of the meeting, the High Commissioner delivers a summary of the discussions and highlights elements for follow up. The themes of the Dialogue included protracted refugee situations; durable solutions and international migration; challenges for people of concern to UNHCR in urban settings; faith and protection, protection at sea, root causes for displacement, protecting the internally displaced, and protection gaps and responses in the existing international protection framework for forcibly displaced and stateless people.
http://www.unhcr.org/pages/501a39166.html

Global Processes addressing human trafficking and migrant smuggling
UNODC Congress on Crime Prevention and Criminal Justice

Established 1955
United Nations United Nations Congresses on Crime Prevention and Criminal Justice (before 2005 United Nations Congresses on the Prevention of Crime and the Treatmentof Offenders) have been held every five years since 1955 dealing with a vast array of topics.They have made a considerable impact on the field of international crime prevention and criminal justice and influenced national policies and professional practices. As a global forum, the Congresses enable the exchange of information and best practices among States and professionals working in this field. Their overall goal is to promote more effective crime prevention policies and criminal justice measures all over the world. 
Translational organized crime has been discussed at the 9th Congress in 1995 in Egypt and the 11th Congress in 2005 in Thailand. The agenda of the Twelfth Congress in 2010 in Brazil focused on children, youth and crime; smuggling of migrants; trafficking in persons; money-laundering; and cybercrime.  The Salvador Declaration on Comprehensive Strategies for Global Challenges: Crime Prevention and Criminal Justice Systems and Their Development in a Changing World, which was endorsed by the General Assembly in its resolution 65/230. The 13th Congress in Qatar in 2015 held a workshop on trafficking in persons and smuggling of migrants, while the 14th Congress was held in Japan in 2021 with calls for stronger partnerships among different parts of the international community to achieve the Sustainable Development Goals and build a more just world. 
http://www.unodc.org/congress/en/previous-congresses.html

Global Processes addressing on an ad hoc basis humanitarian aspects of migration
International Conference of the Red Cross and Red Crescent
(RCRC)
Established 1967
The International Conference is a unique forum bringing together the world's largest humanitarian network and nearly every government.  The Conference members include all States party to the Geneva Conventions and all Movement components – the ICRC, the International Federation and the 190 national Red Cross and Red Crescent Societies. A range of other humanitarian and development actors also participate as observers – including regional and international organizations, the United Nations and several of its specialized agencies, non-governmental organizations, academic institutions and others.
In addition to formal decisions (resolutions) of the Conference, participants also make commitments in the form of pledges. These pledges, which may be made individually or jointly by several participants, are an important tool for translating the Conference outcomes into action at the country level.
http://rcrcconference.org/international-conference/about-the-conference
https://www.icrc.org/en/who-we-are/movement/international-conference

Global Processes addressing on an ad hoc basis labour aspects of migration
International Labour Conference
Established 1919
ILC brings together the tripartite delegations from ILO’s 185 member States and is a forum for discussion of key social and labour questions and adoption of international labour standards, including standards which directly address the situation of migrant workers. 
 

Dormant global processes on migration

The Berne Initiative
Established in 2001, completed its mission in 2005
One of the first state-led global dialogues on migration, the Berne Initiative, explored in 2001-2004 the possibility of developing of harmonized international policy framework on migration, and elaborated a non-binding international reference system and policy framework on migration management to foster interstate dialogue and cooperation at the bilateral, regional and global levels. 
The Berne Initiative was a States-owned consultative process with the goal of obtaining better management of migration at the national, regional and global level through enhanced cooperation between States. The most important outcome of the Berne Initiative process is the International Agenda for Migration Management (IAMM), a reference system and non-binding policy framework aimed at facilitating cooperation between States in planning and managing the movement of people in a humane and orderly way. The IAMM was developed by States as the principal actors in the field of migration management, with the advice and support of other relevant stakeholders. It gathers States’ common perspectives and understandings on migration in a comprehensive and balanced framework in the form of a non-binding agenda, mapping out in a comprehensive manner all major aspects of migration at the international level. The IAMM includes such issues as migration and development, human rights of migrants, labour migration, integration, irregular migration, trafficking in human beings and migrant smuggling, trade and health issues, and return.

United Nations High-Level Dialogue on International Migration and Development (HLD)
Established 2006, dormant since 2019
The purpose of the high-level dialogue is to discuss the multidimensional aspects of international migration and development and identify appropriate ways to maximize its development benefits and minimize its negative impacts. 
http://www.un.org/en/ga/68/meetings/migration
HLD 2013 section on IOM website 

UNHCR Global Consultations on International Protection
2001-2002
Endorsed by the United Nations General Assembly (UNGA) and UNHCR's Executive Committee (ExCom) and welcomed by the United Nations Secretary - General, UNHCR's Global Consultations sought to promote the full and effective implementation of the 1951 Refugee Convention, to develop new approaches, tools and standards to ensure its continuing vitality and relevance, to revitalize the international protection regime and to discuss measures to ensure international protection for all who need it. The Global Consultations took place throughout 2001 and continued in 2002 against the background of debate around large and protracted refugee situations, the high costs of asylum systems in industrialised countries, the burden on developing countries of hosting refugees, and the real or perceived abuse of asylum systems. The process involved governments, non-governmental organizations, other groups and experts which continued into 2002 with an Agenda for Protection - a series of activities which will serve as a guide in strengthening refugee protection. 
https://www.unhcr.org/3ae68c7e0.html