When a subscriber is globally unsubscribed, they will no longer recieve any emails from your organization.

When a subscriber is list unsubscribed, they will no longer recieve emails from the particular lists that they have been unsubscibed from and continue to recieve emails from lists that they are subscribed to.

List based unsubscribes are useful for preference centres as it allows subscribers to choose lists they wish to unsubscribe from, those lists could refer to specific product categories, email send frequencies and more.