According to the leaker ViewerAnon -for those who didn't know, they're the ones who leaked the news about the upcoming The Last of Us HBO show- that Neil Druckmann (Naughty Dog's co-president) is in charge of the next game in line, The Last of Us 3 (or The Last of Us Part 3 if you will). And that it’s currently in production at Naughty Dog.
There are also rumors and talk about a new Uncharted game, which will be a reboot, and will be developed by different Studio (unknown at the moment).