Yes, Storm is a part of the X-Men, BUT, I have to call her out individually for one specific reason: her connection to Black Panther and Wakanda. In the comics, she and T'Challa develop a romance, and practically invented the phrase "power couple." They were together until the battle between the Avengers and X-Men caused a rift in their relationship and they decided to call it quits. (Being embroiled in a fight with super-humans makes your love life so much more complicated, amiright?)
I totally ship T'Challa (Chadwick Boseman) and Nakia (Lupita Nyong'o) in the MCU, but I'd also be lying if I said I wouldn't geek out if Black Panther and Storm interact in some way on screen — or if there was at least a subtle nod to their comic book bond.