When looking for unsubscribing a contact from a Sequence, you'll need to follow these steps:
Note: Unsubscribing a Contact from a Sequence won't unsubscribe them from receiving messages from your Organization, it simply completes the process within that Sequence.
Go to the Sequence you are working with
Go To Contacts > Click on The Checkmark
Click on Remove Contact, it will be moved to status Finished on your Sequence
