That would be the first key implication of Professor X’s appearance in the MCU.
The introduction of the Illuminati in the MCU
The return of Charles Xavier and that scene with six chairs would be a clue that illuminatione of the most powerful groups of superheroes from Marvel, appear in the MCU.
That group is formed, in the comics, by the most intelligent, wealthy and influential heroes, specifically: Tony Stark, Professor X, Namor king of Atlantis, Black Bolt, king of the Inhumans (who have his series), Reed Richards (aka Mister Fantastic) and Stephen Strange himself, although, by the looks of it, this is not a founding member of the illuminati in the UCM, according to what happens in the trailer.
This group of superheroes operates in secret sharing privileged information about threats to Earth and the Universe, forming a kind of conclave of the rich and powerful in the shadows.
We’ll see how that plays out in the movie universe, but the illuminati they have been the protagonists of several important stories in comics and are a weighty addition.
The integration of the X-Men
The clearest implication of Charles Xavier appearing is that, with Disney’s purchase of Fox, The X-Men, and mutants in general, finally live in the UCMinstead of in this weird and awkward separate universe they had.
That means that some of the most charismatic superheroes, who have never appeared before, can finally be integrated into the Marvel Universe.
Many of us are waiting for what reinterpretations and stories they will have after the debacle of the last films, because They can be an important reinforcement for phase 4 and later of the UCM.
The introduction of other major new superheroes and supervillains
There is no doubt that the superheroes of the first films have a lot of charisma, but either their time is up (Steve Rogers’s Captain America, Black Widow or Iron-Man, for example) or it is about to.
But the Marvel Cinematic Universe does not stop and you must replace those heroes with others who maintain popularity and the pull of the franchise.
It’s not an easy thing to do, given the success of the original Avengers, for example. But both the appearance of the illuminati as the ultimate integration of the X-Men, it may lead to us seeing new comic book favorites.
We are mainly talking about Namor, King of Atlantisan important absence, but, above all, of the fantastic 4.
Let Professor X appear as illuminati can also bring in Reed Richards, leader of fantastic fourhow mistreated they have been by the movies.
Many fans are waiting for the reboot Marvel makes of that group of heroes, if it decides to do so.
But the implications do not end there.
We are talking also that the door is opened to epic villains like Doctor Doom or Galactus, for example. Following the departure of Thanos, another major threat is needed to take on the Marvel superheroes and those are two excellent choices for a longer Infinity Stones-style story arc.
As you see, a small detail opens the door to a lot of consequences. The mutants have officially landed, maybe the Fantastic 4 too, and a new batch of heroes and villains is in the offing. And all this, with just a phrase and a glimpse of the character of Charles Xavier.