It has long been confirmed that the actual title of Avengers 4 will be a huge spoiler for Avengers: Infinity War, with some speculating that the title will be revealed after the post-credit sequences in Avengers: Infinity War, since Marvel traditionally has a title card at the very end of their films that says “The Avengers will return” and the title of the next movie.
This means that the title reveal may happen much further down the line than anticipated, and may not come directly at the end of Avengers: Infinity War.
Anthony and Joe Russo direct both Avengers: Infinity War and Avengers 4 from scripts by Christopher Markus and Stephen McFeely, who all previously worked together on Captain America: Winter Soldier and Captain America: Civil War.
There will likely be no plot details for Avengers 4 released until after Avengers: Infinity War hits theaters on April 27 either, and even if there is an official synopsis reveal, it likely won’t be too extensive.