Thanos actor Josh Brolin stated that he would be interested in seeing Thanos face off against Doctor Doom in a movie. He likes the concept of Thanos battling the character played by Robert Downey Jr., and looks forward to Downey portraying Doctor Doom; however, there is currently no confirmed information indicating that the film will arrange a showdown between the two.
When previously asked about the possibility of Thanos returning in the future, Brolin did not give a definitive answer. This time, he expressed interest in the idea of a confrontation between the characters, but did not confirm his involvement in any related films or reveal any story details.
In Avengers: Endgame, Downey's Iron Man defeated Thanos. Some fans have drawn parallels to the comic book Secret Wars, where Doctor Doom clashes with Thanos, sparking discussions on social media about whether the film might borrow similar plot elements and speculating that Thanos could appear in Avengers: Secret Wars. There is currently no confirmed information indicating that the movie will feature Thanos' return or film this showdown.