So, very recently, James Gunn announced a sequel to the 2025 Superman film called “Man of Tomorrow”, slated for release in July 9th 2027. The only thing we do know about it besides it being a sequel, is that Lex Luthor will have his War Suit, going off the photo Gunn shared in the announcement.
As for what I think the film will be about, I’d imagine it would have something to do with Brainiac, who I’m guessing will be the main villain of this film. And Superman will haft to stop Brainiac’s invasion of Earth. I’d also imagine that they probably wouldn’t do something like introduce Batman or Wonder Woman into it, and make sure the cast isn’t overly bloated.