In 1993 Marvel sold the rights of Spider-Man to Sony and X-Men, Deadpool, and Fantastic Four to 20th Century Fox. When The Walt Disney Company acquired 20st Century Fox in March 2019, MCU fans couldn't help but wonder when they'd bring in these iconic Marvel Comics characters to this thriving cinematic universe. Sony and Disney are now on their second deal sharing Spider-Man between the two studios.

The MCU has been met with critical success and an outrageous $22.5 total box office over the course of their first 23 movies. After Avengers: End Game, it was clear Marvel Studios was finished with a few characters, so the influx of these newly acquired Fox properties could be huge for their future success.

X-Men created their own cinematic universe over the course of 13 films, but 2015's Fantastic Four reboot failed at the box office and critically. A fresh start for Marvel's first super-team would be a welcome addition to the well established MCU. 

CONFIRMATION

At the 2020 Disney Investor Meeting, Kevin Feige officially announced a Fantastic Four film being directed by Spider-Man: Homecoming and Far From Home Jon Watts:

 

WHAT THIS MEANS

It was the biggest question whether the X-Men or Fantastic Four would join the MCU first. We finally got our answer today. 

One of the biggest challenges Kevin Feige and Marvel Studios will face is explaining The Fantastic Four into the current MCU. There's no conceivable way that a brilliant scientist like Reed Richards has just been in the shadows all of these years. So there are a few fan theories that are worth repeating. The Avengers tower is clearly for sale in Spider-Man: Far From Home and after the movie showed a sign outside of the tower reading, "We can't wait to show you what comes next." with the numbers "1", "2", "3", and "?" where the "4" would have been, movie-goers quickly speculated that this was in fact an Easter egg that The Fantastic Four will transform Avengers Tower in the Baxter Building. Another theory and rumor is that the upcoming Ant-Man and the Wasp: Quantumania film will introduce F4. A major part of this theory is that The Fantastic Four are trapped in the quantum realm, similar to Scott Lang in Endgame. This would explain why Reed Richards or Sue Storm weren't around during most of the events we've seen in the MCU.

With Jon Watts at the helm, it raises a few questions. Does this mean Watts is finished with the Spider-Man films after the upcoming Spider-Man 3? Or does this announcement mean it's likely that Spider-Man could appear with The Fantastic Four (similar to the original comics from the 1960s)? What we do know is that Jon Watts is greatly inspired by the late John Hughes and his comedic-adventure style of storytelling. We've seen that style in Spider-Man: Homecoming and Far From Home so anticipated a similar style and tone to this film. After Josh Trank's darker take on the characters in 2015, it is unsurprising to see a more light-hearted version of The Fantastic Four in the works at Marvel Studios.