Industry insider FateUnknown, known for their generally accurate leaks, claims that NetherRealm Studios planned a third Kombat Pack for Mortal Kombat 1 but ultimately cancelled it.
According to the insider, the studio intended to release Kombat Pack 3 alongside a second story expansion, but poor sales of the Khaos Reigns DLC reportedly prompted a change of plans. FateUnknown also noted that NetherRealm Studios may still release one or two unannounced Kameo fighters, as they were already in development. No details were provided regarding the potential characters for Kombat Pack 3.
It's worth noting that Ghostface from the Scream franchise was recently added to Mortal Kombat 1, with the T-1000 from Terminator 2: Judgment Day and Conan the Barbarian slated to appear in the future.