Joe and Anthony Russo have explained why they began filming Avengers: Doomsday before finalising the script, saying they treat the screenplay as a "living organism" that evolves once actors are cast. Joe Russo told the Associated Press that as improvisation- and rehearsal-based directors, they prefer to see what actors bring to their roles, even when cast members are confirmed only days or weeks before their scenes are shot. The approach reflects the brothers' broader directing philosophy, previously used on Avengers: Endgame, and comes as the pair also address the film's role in steadying the Marvel Cinematic Universe after a rocky stretch.

Avengers: Doomsday is due for release on 18 December as part of Phase 6 of the MCU, following on from 2019's Avengers: Endgame, which the Russos also directed. The film will unite heroes from multiple universes, including the Avengers, Black Panther's Wakandans, the Thunderbolts (New Avengers) from Earth-616, the Fantastic Four from Earth-828 and the original X-Men. Anthony Russo said their job was not to resolve the entire MCU but to find the "intersection" where these disparate threads make sense together, amid ongoing debate about superhero fatigue that recent hits like Spider-Man: Brand New Day appear to have countered.