Note that spoilers are ahead for those who have not watched the Season 3 finale of Supergirl!
As the Season 3 finale wrapped up for Supergirl, fans were left with lingering questions – but one of those has been definitively answered by Executive Producer, Robert Rovner: Chris Wood will not be returning for Season 4.
Rovner told TVLine that was always the plan for Wood’s character, Mon-El. “The plan for Chris was always to have him on the show for two years,” Rovner explained. “We’ve loved telling Mon El’s story, as well as the story we’ve told for him and Kara. We hope the fans felt that it was a satisfying conclusion.”
Source: IGN.com A Supergirl Actor Won't Be Returning and What's Next for Season 4