Log user Login to Activity Feed for Auditing
When a user logins into the Atlas Portal this is logged to the Activity Feed.
This feature would allow to better user auditing and identify potential security breaches.
One option available today is configure identity federation (https://docs.atlas.mongodb.com/security/federated-authentication/) and then use the auditing that your IdP offers.
Note that Atlas audits any material action taken within the MongoDB Cloud UI (cluster configuration changes, security configuration changes, data explorer usage, etc).