The Atomic Heart: Annihilation Instinct DLC is already available!
Check out the launch trailer:
New narrative content, a new Mendeleev Complex area, new weapons, new shape-shifting enemies, and a new glove's ability await you now! Hurry to meet an enigmatic Professor Lebedev to figure out how to suppress the AI’s insanity and curb NORA’s annihilation instinct!
Source: YouTube