Marketing Cloud Engagement lets you add subscribers to a suppression list in Email Studio via an Automation Studio import activity, SOAP Web Services API, or the import wizard in Email Studio Suppression List. The subscriber must be imported without a status column. Subscribers can also add themselves to public suppression lists via their subscriber center. When a subscriber uses a one-click unsubscribe, the subscriber is added to the suppression list. The subscriber remains on the list, data extension, or publication list with a status of Unsubscribed.
Note If a subscriber is imported into a suppression list with the status of Unsubscribed, this
action results in an inactive record being added to a suppression list. If the subscriber
being imported exists in an active status, they’re no longer visible in the suppression list
and are deactivated from the list.