There are quite a number of movies under Marvel's Phase 3 lineup already; however, there is one that has left fans wondering about if it will be made. Could "Iron Man 4" be among those films that Marvel has planned in the years to come?

Robert Downey Jr. denied any speculation that an "Iron Man 4" is going to happen, as he told Variety back in 2014. The actor, who has played Tony Stark/Iron Man for nearly 10 years, stated that there are no plans for a fourth solo movie. However, it still does not stop the rumor mill from turning now that Marvel has revealed some of the movies that are up for release in the coming years.

"Black Panther," "Avengers: Infinity War" and "Ant-Man and the Wasp" are all set for 2018, while Brie Larson's solo outing as "Captain Marvel" will hit theaters in 2019. There are three that are set for a 2020 release date, but those movies have yet to be determined. Could one of those three untitled movies be "Iron Man 4?"

Apart from the general rumors that "Iron Man 4" could be happening, there are also speculations about the plot. One such rumored plot is that Tony Stark will be mentoring a 15-year old teen named Riri Williams in the fourth installment. Anyone who is familiar with the comics knows that Riri Williams is set to replace Tony Stark as the new Iron Man, or Ironheart, in this case.

Another rumor according to MoviePilot last year is that fellow Avenger Natasha Romanoff a.k.a Black Widow, played by Scarlett Johansson, will be donning the Iron Man suit when Downey ultimately retires from the role. For now, fans can expect to see Downey take on the Iron Man suit in "Spider-Man Homecoming" which just hit theaters everywhere as well as "Avengers: Infinity War" next year.