The new audit trail capability was recently released as part of the latest Adobe Campaign Standard Release 21.3 - September 2021.
TheAudit trailgives you access to the complete history of changes made within your instance. It captures, in real-time, a comprehensive list of actions and events occurring within your Adobe Campaign Standard instance.
For more details, refer to this detailed documentation: Audit Trail
Please feel free to reach out through the below comment section in case you have any questions.