Lately, I feel like all I get is spam email. This is very frustrating and I've taken to using apps like Unroll.Me that make it easy to unsubscribe from the bevy of email lists I've somehow wound up on. That being said, it appears Apple has baked the ability to unsubscribe from mailing lists straight from the native Mail app in iOS 10.
iOS 10 tidbit: unsubscribe from mailing lists from the Mail app