Simon Williams/Wonder Man has quite the complicated history; he started off as an Avengers villain, but later joined the team. His villainous brother, Grim Reaper, later teamed up with Ultron and used Simon's brain patterns to create Vision (who, in the Marvel Cinematic Universe, is a combination of Tony Stark, Bruce Banner, Ultron, and J.A.R.V.I.S.).
There's a lot Marvel Studios could do with the character and his complex history, and a recent WandaVision featurette with Wonder Man concept art in the background got everyone talking. There's no way its inclusion was an accident, and while it could be something as simple as a rejected Halloween costume, you'll find plenty of theories online about how the MCU could use Wonder Man!
In a recent interview with The Playlist, WandaVision showrunner Jac Schaeffer was asked about the artwork, and chose her words extremely carefully!
"I was standing in our writers’ room, which is covered floor-to-ceiling in all sorts of art and inspiration," she teased, "and it’s a pretty exciting room and...yeah..." That's not much to go on, but there's clearly something Schaeffer can't or won't elaborate on!
As for whether she has a future in the MCU beyond WandaVision and Black Widow, the writer added: "I would consider myself incredibly lucky to work on more Marvel projects, so we’ll have to see."
Well, she's definitely got the classic Marvel Studios secrecy perfected, wouldn't you agree?