Untitled fifth Avengers film

Note: This isn't fanfiction. There was going to be a 5th Avengers film until it got cancelled (Wikipedia had it on Walt Disney Studios films (2020-2029) until it got removed).

After the release of Avengers: Endgame, there was a future for the MCU.

Why It Was Cancelled

 * 1) Kevin Feige announced that Endgame was the final installment of the Avengers franchise.
 * 2) Natasha Romanoff and Tony Stark both died in Endgame, as well as Steve Rogers retiring.
 * 3) Endgame became one of the most expensive and highest-grossing films of the 2010's decade.

Results

 * 1) The film was permanently cancelled.
 * 2) The Avengers films are now a quadrilogy.