This M18/R-rated movie carries a warning about “violence and coarse language”. You might think that’s standard boilerplate for any action movie, and maybe it is, but in this case, they’re really not kidding.
In case you missed the first Deadpool movie, Deadpool is a basically immortal, literally scarred super-anti-hero in a skin-tight red-and-black suit that, like Spider-Man’s, covers his whole head and eyes, and unlike Spider-Man’s, has two long swords attached to the back. Deadpool’s human name is Wade Wilson. The name “Deadpool” refers some kind of bet about who was going to die soonest, which turned out to be not Wade, obviously.
Deadpool spews a steady stream of pop-culture references, curses, and insults, often talking directly to the audience about how he’s in, like, the mother of all superhero movies. The Deadpool movies are thus not just violent, coarse fantasy/action movies, they’re parodies: each one is a sustained self-reference joke, complete with ironic use of 80s light-rock hits. (The 80s are so trendy these days!)
The second Deadpool movie, as Deadpool himself tells us, is not for kids, but is nevertheless “a family movie”. As becomes clear towards the end of the movie, he’s not talking about the genre of the movie, he’s talking about the theme of the movie. The movies in the Fast and Furious series were also “family movies” in this sense: the characters consider each other family because they derive their identity from their strong bonds with each other.
What group of people/mutants could Mr. Pool possibly belong to? Is he talking about starting a literal family with his girlfriend (who will never not look like Inara from Firefly to me)? Is he joining the largely but not entirely absent team of X-Men? Is he forming his own superpowered vigilante crew? How about all of the above? Yeah, kinda!