Very little is known about the Marvel Cinematic Universe Phase 4 other than the fact that "Guardians of the Galaxy Vol. 3" is going to be in it. However, as stated in a report from Yibada, there is a chance that "Iron Man 4" could be included but with Robert Downey Jr.'s Tony Stark passing the torch to a younger, female character.

Marvel Comics already did so when they introduced 15-year-old Riri Williams as the new Iron Man. In the comics, she was already capable of making her own mock-up of the Iron Man suit and was able to fly it but despite her skill and intelligence she got in trouble at school for it, at least until Tony Stark met her and named her as his successor.

It is possible that this could happen in the films. In numerous past interviews Downey Jr. has hinted he could still come back but sometimes he might not. Yibada points out that the actor has even called "Captain America: Civil War" a mini "Iron Man 4."

Fans speculate that Ty Simpkins' character from "Iron Man 3" might become the successor in "Iron Man 4" given that the actor would be older by the time the film entered production and release. However, it is still possible a female will be cast instead so that the films can adapt the Riri Williams character. 

Downey Jr. even supported the concept of a female Iron Man back in July, when he posted a photo on Twitter showcasing the cover for the new "Iron Man" comics where Riri Williams was the lead star and Tony Stark only served as her mentor.

It is pointed out that this kind of mentor-role has already been displayed in the films. During "Captain America: Civil War" Tony Stark was a mentor for Peter Parker aka Spider-Man (Tom Holland) and he is set to reprise this role of mentor in the upcoming "Spider-Man: Homecoming" film.