Explanation
Access Team template
The privileges assigned to the access team through Access Team Templates. Access Team template allows you to create a template for the entities on which "Access Teams" option is enabled. You can grant or restrict access to the entity records through "Access Rights". Essentially, this is like a record-based security model on an entity record for specific users.
Once the access team template is created and added to the entity form, you can start adding users. For example, on an opportunity record add a new user in the Access Team Template sub-grid.
Reference:
https://community.dynamics.com/crm/b/crmdevmigrationconfigandcustomization/posts/access-teams-and-access