In the Settings dashboard of your account you can manage the Footers that are used for outgoing emails. Support commonly receives questions around link tracking in Footers, will clicks on these links be reported in campaign reports?
When editing a Footer, checking the "tracked" box for the unsubscribe link (or a preference center, if used instead) will track click activity on the link:
Though not common, it is possible that your account settings are configured to not track links. In Settings > Account Management > General Account Settings > Settings tab (right menu) there is a check box to enable click tracking. If the box is not checked here, but at the Footer level the "tracked" box is checked for the unsubscribe or preference center, the only link in the Footer that will be tracked is that link. Tracking configuration at the Footer level overrules the tracking configuration in the General Accounts Settings page.