The confirmation of Future West City (In Ruins) being in the game hints at Dragon Ball Super characters Vegito Blue, Goku Black, Zamasu, and Fusion Zamasu being playable.
That is another hint that we may see Vegito Blue, Goku Black, Zamasu, and Fusion Zamasu in the game.
This is the battle arena where Super Saiyan Blue Goku and Super Saiyan Vegeta battle Goku Black and Zamasu initially and then later on Vegito Blue fights Fusion Zamasu.
Also it’s where Future Trunks battles Goku Black, Zamasu, and Fusion Zamasu.