At first, I thought XCOM 2 couldn't work with AR thanks to its rigid strategic combat. It wasn't until I watched Directive Games' prototype, The Machines AR, that I was convinced of what AR could do.
XCOM 2 would be able to work as a miniature battlefield that could be taken on any surface becoming a warzone between humans and aliens. This would bring out the tactician inside all of us while providing a fun and creative look at this universe. While this wouldn't be a perfect solution -- I don't think you could merely port XCOM 2 into an AR game -- there would definitely be potential for the series in this space.
On the more playful end of the spectrum, Tiny Metal could also be a nice alternative thanks to its cartoonish, toy soldier appeal. This would work if you keep the cartoon style the game has and advertise it as a kids' miniature battlefield. Mimicking an experience many have gone through growing up, playing with miniature army men having a massive battle -- but this time, it would be through the power of AR.