Well, you're using another game's name in your own game's title. The XCOM name is subject to Intellectual Property rights. I don't think you'll have any issues as long as your game is still not much known, but you'd rather change it in the future (if you wish to continue working on it). If you're looking for a game genre, I think the label 'Tactictal RPG' would be the closest, even though it is expected to have some form of movement/positioning involved in the combat.