Team are a way to group users together for the purposes of allowing access to certain projects. Organization Administrators can access Organization Settings - Teams to create and manage new teams.

Teams can be added to Projects so that all members of the team have access to the project. As you manage team membership, project access is automatically reflected.

A project by default has no project members, and all users in the tenant have access to it. In order for access control to be implemented, a project member mapping must exist. When a project member mapping exists: The user’s role with respect to a project is the highest project role across project member mappings. When no project member mapping exists: all users have access.

Organization Admins (users with the admin role under Organization settings | Users) can also manage project membership through this interface. Organization Admins will be able to see projects even if the project has a team associated that the admin user is not part of. 

Organization Admins will also retain their admin privileges if they are added to a team with member access to a project. On the other hand, a user with the member role will have admin privileges if they are added to a team with admin access to a project. The owner of a project (derived from the owner field of project) always has “admin” project member privileges for that project.