This is what Harington, the actor and driving force behind the project, says. Harington was reluctant to talk about the spinoff when it was still in the idea stage "because during development you look at every angle and see if it's worth it," he told Screen Rant. “And right now it's not. Right now it's off the table because we couldn't find the right story to tell that we were all excited enough about. So we decided to call it quits for now. Maybe that We will come back to it in the future, but not at this time. It is firmly on the shelf."
In June 2022, it was announced that there would be a potential series, a sequel to Game of Thrones with Harington's character Jon Snow at the center. After the leak, author George R.R. Martin that the series had Snow as a working title and that there were writers/showrunners on board, brought in by Harington.
At a GoT convention in December 2022, Harington theorized what could happen to Jon Snow after his character kills Daenerys at the end of the parent series.
“I think if you asked him, he would’ve felt he got off lightly,” Harington said. “At the end of the show when we find him in that cell, he’s preparing to be beheaded and he wants to be. He’s done. The fact he goes to the Wall is the greatest gift and also the greatest curse.”
There are currently two Game of Thrones prequel series, House of the Dragon, which is starting its second season, and the upcoming A Knight Of The Seven Kingdoms, which is currently in casting.