Theres growing speculation about Thanos possibly returning in Avengers: Secret Wars. While Thanos met his end in Endgame, the upcoming multiverse-centric Secret Wars opens the door to alternate versions of characters, including Thanos. However, the main focus of the movie is expected to be Doctor Doom, a powerful villain who, in the comics, rules the multiverses Battleworld.
In the Secret Wars comics, Doom defeats Thanos, showcasing his superior power. If Thanos does return in the MCU, it may be as a minor character, serving to emphasize Dooms rise as the new cosmic-level threat to the Avengers. Doom War refers to Dooms multiversal takeover, which the heroes must unite to stop.