Mortal Kombat 1 is NetherRealm's next (and first) game post-WB merger

gamedeveloper.com:

NetherRealm's original fighting series Mortal Kombat is back, this time as Mortal Kombat 1. The developer formally revealed the twelfth main installment in the long-fighting series with an announcement trailer. 

Its last big (read: non-mobile) project was 2019's Mortal Kombat 11, which ended its lifecycle back in 2021. This marks the first time in the studio's 13-year history that it has gone from one Kombat entry to another, rather than switching over to its other franchise, Injustice. 

NetherRealm has been teasing Mortal Kombat 1 in recent weeks, following a mention of its existence by Warner Bros. Discovery CEO David Zaslav back in February. More recently, details such as its guest characters and general plot were leaked ahead of the larger reveal. 

Mortal Kombat 1 is meant as another reboot of the series' ongoing narrative, which had its first reset back with the studio's debut game, 2011's Mortal Kombat (aka, Mortal Kombat 9). It's currently slated for a September 19 release on PlayStation 5, Xbox Series X|S, PC, and Nintendo Switch. 

For NetherRealm, Mortal Kombat 1 also marks its first game in the wake of the shifting business for parent company Warner Bros. 

In 2020, it was reported that WB Games was potentially up for sale. Publishers like Take-Two and Microsoft were reportedly interested in acquiring the video game division and its studios, which includes Rocksteady (Batman: Arkham) and Monolith Productions (Middle-earth: Shadow). 

With that uncertainty in mind, you can see why NetherRealm would opt for another Mortal Kombat rather than Injustice 3. It's safer to make a game for a franchise a developer already owns than one that requires characters it may suddenly not be allowed to use without potential licensing