Through the Mailgun Documentation, there are 3 unsubscribe links:
%unsubscribe_url%
link to unsubscribe recipient from all messages sent by given domain%tag_unsubscribe_url%
link to unsubscribe from all tags provided in the message%mailing_list_unsubscribe_url%
link to unsubscribe from future messages sent to a mailing list
The documentation references being able to unsubscribe from campaigns: here.
How do I add a campaign_unsubscribe_url or something similar?
Currently, I am working around by tagging.