Bandai Namco recently put out a tweet that was promoting an upcoming Dragon Ball Z action RPG game that is due to be released this year. The tweet also stated that a character from Universe 11 was coming to Dragon Ball FighterZ and that more information was going to be revealed at the world tournament that was being held for the game.
It seems that the people at V-Jump beat Bandai Namco to the punch, as a leaked image from the upcoming issue of the magazine (via Event Hubs) confirms that Jiren will be coming to Dragon Ball FighterZ, which is the character most fans assumed would be representing Universe 11.
We still don't know if Jiren is a one-off character or will be part of a new season of DLC characters, but it seems unlikely that a single new character would be added to the game following the first round of DLC.
Jiren is one of the most highly requested characters for Dragon Ball FighterZ, as he spent most of his time in the Dragon Ball Super anime beating up the main cast, to the point where it took an alliance between Android 17, Goku, and Frieza in order to defeat him.
It's possible that we will see other members of the Pride Troopers (Jiren's comrades) as other DLC characters in Dragon Ball FighterZ, otherwise, they may appear in cameos during some of Jiren's moves, as Chiaotzu does with Tien.
Dragon Ball FighterZ had eight characters in its first round of DLC (Android 17, Bardock, Broly, Cooler, Base Goku, Base Vegeta, Vegito, and Fused Zamasu), which means that we may see an additional seven DLC characters released after Jiren.
Ultra Instinct Goku seems like an obvious choice for another DLC slot, which leaves six positions for the likes of Janemba, Toppo, Whis, Yajirobe (as if), Shin, and Kefla to appear.
The official announcement for Jiren will most likely be on either January 26th or 27th, when the world tour finals for Dragon Ball FighterZ take place.