https://wccftech.com/the-last-of-us-3-story-outline-already-drafted-but-the-game-isnt-being-made-yet/

Speaking to the Script Apart podcast, usually reserved for discussing films, Naughty Dog's Neil Druckmann confirmed that he already drafted a story outline with co-writer Halley Gross of what would happen in The Last of Us 3.

I don’t know how much I want to reveal. Halley Gross and I did write an outline for a story, that we're not making, but I hope one day can see the light of day – that explores a little bit what happens after this game. We’ll see.