SCCM Cloud management gateway (CMG) is an Azure service (PAAS) to manage SCCM client over the internet.CMG is an SCCM Management point in Cloud. CMG open up different scenarios for modern device management. This included slides which shows SCCM CMG Schema Workflow and Scenarios. For more details refer : https://www.anoopcnair.com/sccm-cmg-sccm-cloud-management-gateway-part-1/