Phantom Liberty is the only planned Cyberpunk 2077 expansion
It will be arriving in 2023.
Most people would probably agree that The Witcher 3: Wild Hunt was a brilliant game, that was enhanced even further by the two very well made expansions Hearts of Stone and Blood and Wine, which felt like brand new mini adventures.
It has been known for some time that the studio's latest game, Cyberpunk 2077, would also be fleshed out with expansions, and recently Phantom Liberty was revealed. But it seems like this will be the only expansion we're going to get for the game, despite the studio previously claiming that there would be two of them.
In the YouTube comments for the Phantom Liberty trailer yesterday, the official CD Projekt Red account wrote to a fan: "Glad to hear we sparked your interest! As for the future, Phantom Liberty is the only planned expansion for Cyberpunk 2077."
A very reasonable guess is that CD Projekt Red's extremely botched launch of the game and the massive undertaking in restoring it, has simply taken too many resources from the studio. They probably want to move on to other projects like the upcoming The Witcher game instead to get a fresh start instead of patching up Cyberpunk 2077.