Everyone is wondering how the X-Men will ever fit into the existing MCU, but one of the theories of “Avengers: Finale” offers a logical way how this could happen. During the Infinity War, Thanos collects the last stones he needs to destroy half of the universe. After killing Vision for the Mind Stone, Thanos uses it to fulfill his promise. This is a huge amount of power, more than any creature before him.
After the Infinity War, the heroes try to track down Thanos to find him, defeat him, and use the Infinity Stones to bring everyone who died during the click back from the dust. The search for Thanos continues until Nebula remembers where he always said he would go after he made a click: The Garden. Upon learning of this, Rocket Raccoon says: “When Thanos snapped his fingers, the Earth became the epicenter of a power surge of ridiculously cosmic proportions. No one has seen anything like this two days ago on this planet.” The Avengers then go after Thanos and find out that he used the stones to facilitate their own destruction, which must have caused a second huge burst of energy.
After robbing time, the Avengers collect all the stones and use the Hulk to bring everyone back to life, allegedly causing another giant power surge, this time on Earth. Then, when Thanos returns and threatens to destroy 100% of life in the universe, the Avengers add their own infinity gauntlet to the mix to collect all six stones and defeat Thanos’ army, destroying him and his minions. These are the three times when the stones were used on Earth, and the fourth time when Thanos tore the stones out of the Garden. It goes without saying that each of these three power surges coming from Earth triggered a huge chain reaction of events. One theory (via Reddit) claims that this may help explain the appearance of mutants in the MCU.
How the pictures could lead to the appearance of mutants in the MCU
According to the theory, the huge amount of energy released when Thanos, Hulk and Tony clicked created waves around the world, activating the X-gene in humans. Then, according to the theory, over the next few years, the X-genes will begin to activate, which will lead to mutants becoming part of the population. This is a clean and clear way to link previous MCU events to the next phase and perfectly explain why mutants were absent up to this point.
According to this logic, the pictures themselves do not endow people with superhuman abilities, but activate the gene to reveal what has already happened, as it happened with the Scarlet Witch. WandaVision confirms that Wanda did not get her powers from the mind Stone. Or rather, stone-activated abilities that she already had. This suggests that not only stones have this power, but also that Wanda is also a mutant. It’s possible that all the other potential mutants were already there, waiting for activation with something like a latch, and that’s how the X-Men will fit into the existing MCU.