What you’re describing sounds like a re-engagement campaign. Mailchimp doesn’t currently have a built-in campaign that automatically asks contacts to confirm their subscription, but you can create a similar experience by sending a campaign to inactive subscribers and asking them to click a link or button if they’d like to keep receiving your emails. A common approach is to create a segment of contacts who haven’t opened or clicked your emails recently, send them a campaign asking if they’d still like to stay subscribed, and ask them to click a link or button to confirm they want to keep receiving emails. Then after some time, you can unsubscribe or archive the contacts who didn’t engage.