The Guardians filmmaker is currently gearing up for Peacemaker Season 2, which will help expand the DCU. The first movie Superman featured a number of other heroes, but it's unclear what the plan is for Aquaman. While on the Peacemaker podcast, Gunn was asked about about the character formerly played by Jason Momoa, and he said:

While going over the first episode of Peacemaker, DC Studios co-head James Gunn clarifies whether or not Aquaman is canon in the DCU.

DC Studios co-CEO James Gunn has confirmed which scene from the first episode of Peacemaker Season 1 won’t be canon to the DC Universe. This comes ahead of the John Cena -led DCU series’ HBO Max return on August 21 for its long-awaited second season.