The new Access Control uses a new approach to granting access leveraging Assignments & Permissions, Resource Pools and User Roles. The old Command Control Console operates differently.
The two do not have a relationship other than when access is determined, Access Control is determined first for authorization and then if no suitable authorizing policy is determined, then the request is deferred to Command Control to attempt to authorize. So Access Control takes precedence with backwards-compatibility into Command Control if any rules are relied upon there. So both can exist at the same time for now.

The two are unrelated and different approaches in handling policies. Access Control has some big improvements over Command Control, but creating Assignments in Access Control are not synchronized into Command Control and vice versa.

From documentation, "You can either use Command Control or Access Control based on the relevance and the environment. You can enable or disable either Command Control or Access Control policy engine, by going to Settings > > Server Settings > Policy Engine. Use the slider to enable the status of either the Access Control Engine or the Command Control Engine."

For more information on Access Control, see https://www.netiq.com/documentation/privileged-account-manager-40/npam_admin/data/t4dyttmbta63.html