Marvel Studios initially made it seem like the next two Avengers films would be directly connected, thus the titles of Avengers: Infinity War Part 1 and Avengers: Infinity War Part 2. But the studio later decided that the two films would be different, leaving Avengers 4’s title undecided.
According to Marvel Studios president Kevin Feige, the film’s title hasn’t been revealed—and probably won’t be any time soon—because it would reveal a big spoiler. Feige divulged the bombshell to CinemaBlend in a new interview—which, of course, doesn’t provide any clues as to what the title will be.
(So, I suppose that means we are free to wildly speculate about what the film will be called.)
Marvel has probably dropped clues throughout its previous films hinting at things to come. It may also be somewhat political, as some of the franchise’s biggest stars have contracts that run out relatively soon.
By withholding the movie’s title, it allows Marvel to keep the element of surprise. There’s a pretty good chance not everyone will survive the events of Avengers: Infinity War, so there’s no point of telegraphing that ahead of time, especially since Infinity War doesn’t come out until next year. Remember the terrible nightmare Tony Stark had in Avengers: Age of Ultron? Grim.
Feige goes on to say that the two movies will be very different, which at this point doesn’t mean much. But him saying Avengers 4’s title contains a spoiler is rife for speculation. So, I’m just going to say it: Avengers: The One Where Captain America Dies.