Nah no offense but this is an awful idea.
You can "back ground" explain street level stuff like Daredevil or Spider-Man....you can't say an entire race of people with powers was in the back ground this whole time, but never shown.
And if it's a recent development then people are going to wonder what the catalyst was. And at that point you might as well explain it (the multi-verse, or Wanda doing a reverse "no more mutants").
Fred.
Why not?
We didn't see every news report in the MCU
You could absolutely say that
Mutants exist, but ppl don't know how many they're are
Maybe there's a lot, maybe there's a few
Magneto...already answered that
He has powers, he's been using them, he may have even been going on missions and fighting people, but he hasn't been doing any big terrorist stuff until he has exactly what he needs
He's been doing smaller missions and killing people, and EMP blasts take care of cameras
Why didn't Xavier help during Thanos?
He exists, but he's not a hero yet
Xmen don't exist yet, individual team members are regular civillians
Xavier in the comics isn't going to walk into a horde of space aliens, even if there are other heroes around, like lemme play my part too