Naughty Dog has already written the story of a potential third game in The Last of Us series, but the game is not currently under construction.
Speaking on the Script Apart podcast, Naughty Dog creative director Neil Druckmann said he and co-writer Halley Gross had outlined the story of The Last of Us 3 and wanted to tell what happened after the second game, hoping it would happen one day in the future.
Neil Druckmann said the game was not currently being developed.
Naughty Dog is currently working on several projects. One of them is The Last of Us Part II multiplayer game. The other one isn’t clear yet. After The Last of Us 2, the studio was told that the next game would be either a new IP or The Last of Us 3, and it looks like the new IP.