Explanation
https://docs.microsoft.com/en-us/azure/active-directory/users-groups-roles/groups-dynamic-membership Scenario:
Litware identifies the following identity and access requirements: All San Francisco users and their devices must be members of Group1.
The tenant currently contain this group:

References:
https://docs.microsoft.com/en-us/azure/active-directory/users-groups-roles/groups-dynamic-membership
https://docs.microsoft.com/en-us/azure/active-directory/fundamentals/active-directory-groups-create-azure-porta