This rumor and article are so dubious that I almost decided not to share. It originates from a post by a user on Reddit, that's sparse on detail.

https://comicbook.com/gaming/2019/07/01/tron-new-game-ps5-xbox-scarlett-2021/

The poster of the rumor on Reddit has no posting history, so no track record to go by as to whether this person has been accurate before, or not.

Also, details are extremely vague. Just that it’s supposed to be an "Open World RPG" that ties Single Player and Multiplayer together, has been in development for at least three years, and won’t be coming out until 2021.

The site managed to create a long-winded article out of four short sentences on Reddit, and starts making assumptions while treating them as "facts".

For example, assuming which platforms the game will be on. The article makes it sound like the game will only be coming to the next Playstation and Xbox, as if the author knows this for a fact. It could just as easily come to PC and Switch, too. (Will the game come to the next consoles? Of course. But don’t assume which platforms the game will be releasing on, when you don’t actually know official details. All the rumor said is that the game is supposedly coming out after the "next consoles release". It didn't go into specifics about platforms.)

All that being said, it makes sense for a new TRON game — if there’s going to be one, any time soon — to be released at the same time the TRON roller coaster opens.

I’ve been saying this all along. If any new TRON film/series is going to be in theaters/on Disney+, and/or a new game comes out, it would be in 2021 to coincide with the TRON roller coaster’s opening.

Thanks to another user, Pooker100 on Reddit, for making me aware of this.