If you thought that Robert Downey Jr. was itching to make a Marvel cameo anytime soon, you would be wrong. The infamous actor, who brought Iron Man to life and jump-started the MCU, is done for good. 

According to ETCanada, Downey was on the Smartless podcast hosted by Jason Bateman, Will Arnett, and Sean Hayes recently, and he revealed that he's all done with the MCU. Bateman, who is enjoying a career renaissance with Ozark, was the one to bring up the idea of Iron Man making a cameo. “I’m assuming that the Marvel thing is at a slower speed now, or are you done with that now," he asked Downey.
“That’s all done,” Downey responded.

This could be a lie though. There are rumors that Tony Stark does appear in the Black Widow movie, since everyone in the Avengers was alive during the time period the movie is based on. Still, these are just rumors and there is a chance that old unused footage of Downey was used instead of new scenes. 

For now, Downey is staying in the comic book world by producing the upcoming Netflix series Sweet Tooth, based on the comic by Jeff Lemire.