Summary: Go to learners and click the bell icon to unsubscribe them.
You can manually unsubscribe learners from campaign emails:
1. Go to Learners and use the filter to select the campaign that you'd like to unsubscribe a learner from.
2. Hover your mouse over the name of the learner and click the icon. The learner is unsubscribed and won't receive any more emails from that campaign.