From Marvel Studios News:
That’s a wrap, Cap. Chris Evans announced he has officially wrapped on Avengers 4, thus completing his Marvel Studios contract. While there’s always the chance he could sign up for more films, it appears Evans is hanging up the shield once and for all.
“It was an emotional day, to say the least,” Evans says. “Playing this role over the last 8 years has been an honor. To everyone in front of the camera, behind the camera, and in the audience, thank you for the memories! Eternally grateful.”