Ready Player One by Ernest Cline became a film in 2018 and now it has been nailed down that the sequel Ready Player Two will also be made into a film. Ernest Cline confirmed this in an interview with Inverse in connection with his press tour for the new book and more specifically said this:

“It’s in the early stages right now, especially since Hollywood is in limbo right now. But I can tell from the experience of making the first movie that everybody had a lot of fun.“

https://www.inverse.com/entertainment/ready-player-two-movie-ernest-cline-interview