Email Preferences

The Unsubscribe link at the bottom of a Marketing Cloud Engagement email opts the person out of all further emails from that instance of Engagement. If you want users to be able to unsubscribe from site emails without unsubscribing from other brand or company emails, some setup is required.

Available in: Enterprise, Professional, Unlimited, and Developer editions.
Note
Note Email preferences aren’t automatically synced between Experience Cloud and Marketing Cloud Engagement without customization. Consider discussing implementing a custom subscription center with your integrator or Salesforce services.

The controls for system-generated emails from a site, like comment notifications, are managed within the site by users, not in the Engagement app.