To help protect sensitive data in production and sandbox environments, you can now monitor when users provide login access using the Grant Account Login Access setting. This can be tracked using the Login As event and trigger Transaction Security Policies that automatically alert your admins or block access.
Where: This change applies to Lightning Experience in Enterprise, Performance, Unlimited, and Developer editions.
Who: This change is available to users with the Event Monitoring or Salesforce Shield license.
Why: This change enables users to protect sensitive data integrity and prevent unauthorized changes.