they are though. The 20th century Fox X-Men are in it, So is Deadpool, probably Blade too at some point.

The thing is from a COMICS point of view, unfortunately, this makes sense along with the casting of RDJ as Doom and especially now in this trailer where it highlights the fact Rogers has a kid even more so. let me explain.

a few years ago Marvel redid their Secret Wars arc but called it Battleworld. Basically Doom fused a bunch of alternate marvel dimensions together and called it Battleworld. things like Evil Avengers, Marvel Zombies, 90s X-Men, etc all got merged into this world in separate areas and Doom ruled it all. Now on one of these worlds Rogers had a daughter named Ellie who ended up becoming the leader of a resistance movement against that worlds “Evil Avengers” which I now believe will be a main plot point of these films and the reason Cap is back. He’s not good, he’s the evil version and I believe in this evil avengers version Iron Man IS Doctor Doom or becomes Doom. thus RDJ being cast as Doom as he’ll be the evil version of Iron Man. This is also how they explain bringing in the 20th Century Fox version of the X-Men as well as stuff like Deadpool and Blade and whatever else (venom, ghost rider, daredevil, like 3 versions of the Hulk, etc, etc) so then ALL the previous marvel films from all the various studios will now be officially canon to the mainline MCU thanks to Battleworld.

So them revealing Evans returning as Rogers is sort of a swerve. He’s not the good guy, he’s one of the bad guys. None of these films every deviate in a big way from the various comic sources, there’s always basic plot points. Every movie has been inspired or used plots from the comics, I can’t recall a single MCU movie that was truly an original story. Hell I’d even go as far as to say the X-Men in this film will go after Wanda because in their reality she was responsible for “no more mutants”.