Deadpool has never been much of a team player, which is why the X-Men are a perfect fit for him. They've got a bunch of different teams running around, so he can pick and choose. Most of them end up ditching their teams and going off on solo adventures every couple of weeks, too. Tome of them even seem to have more than one adventure at a time! Warpath is the perfect guy to follow around - he's a moody loner with a talent for finding fights, which is exactly the sort of interaction at which Deadpool excels. Hopefully, Warpath won't mind a little company.