The default Keap / Infusionsoft Unsubscribe link at the bottom of every email sent will mean that that contact will opt out of all your email marketing. It is a pretty blunt tool as you can end up losing the ability to email your best customers, all because they did not want to receive your weekly newsletter for instance.
In the YouTube video below Jamie DuBose gives a great demonstration as to how you can customise Keap / Infusionsoft Opt Out Links.