Most common situations
If you enroll an AD group in a course, then all users from this AD group will be automatically added to the Learner list.
If you add new users in your AD group, these users will be automatically added to the courses, where this AD group was added.
When you remove users from the AD group, these users will be removed from the courses too.
The course progress of this learner will not be shown. The user will be removed from the Learner list if this user was not be enrolled in other courses.
If you enroll an AD group in the "Manage learners" list - in the "Register attendance" list these users will be displayed individually, and not as a whole group.
To remove the Ad group from all systems (to free up the license), navigate to Azure Active Directory admin center> Groups> Delete group. The group will be removed after a little while.