Raven Software's Call of Duty: Black Ops Cold War is definitely not for the faint of heart. We're not just talking about the violent aspects of the game, which of course involve guns and missiles, but also a very real psychological aspect involving the character of Bell. Throughout the game, the player will witness Bell's own unraveling of trauma and a major identity crisis.
Why does Adler kill Bell in Black Ops Cold War?
Combined with Operation Greenlight, the nuclear weapons program determines the final part of the game, where the player must decide how to proceed and reach a final conclusion.
Related: Is Adler Perseus in the Cold War?
Bell discovers who he really is in the mission 'Identity Crisis' and it's not good. All this time Bell was convinced that he was a CIA agent working with Russell Adler, but he discovers that he is actually a Russian agent working with Perseus and has been severely brainwashed by the CIA.