This was announced by Naughty Dog President Neil Druckmann during a speech at Summer Game Fest. A little later, his words were confirmed in the official Sony blog.
Recall that The Last of Us Part II was released in June 2020 on PS4 (and in May 2021 on PS5). In the first three days, it was bought 4 million times, which made the game the fastest-selling PlayStation exclusive.
At the presentation, Drakmann also said that the remake of the first The Last of Us will be released on September 2 on PS5, and soon after on PC. In addition, he announced a full-fledged multiplayer game within this universe, but did not share a lot of details. Drakmann also mentioned that Naughty Dog is already working on some new game, but did not elaborate on the topic.