Avengers: Secret Wars is the final movie of Phase 6 and the end of the Multiverse Saga. Joshua James Brolin is an American actor who appeared in films such as The Goonies, Mimic, Hollow Man etc. He appeared in Avengers: Infinity War and Avengers: Endgame. Other than this, he has played the role of the Marvel character, Cable, in Deadpool 2.
Thanos appeared in Avengers Endgame for the last time where he gets defeated and a deleted scene points towards the hint that thanos may return to MCU.
In several of his interviews, Brolin was always affirmative about accepting the role of Thanos again if and so offered.
It is with the most recent tweet made by the MCU that Josh Brolin will return as Thanos for Avengers : Secret Wars.
Josh Brolin will return as Thanos in #AvengersSecretWars #MarvelStudios pic.twitter.com/Bqje9TgTeI
— Marvel Updates (@marvel_updat3s) January 4, 2023