The Spy Who Came in from the Cold (1965)

In the shadowy world of espionage, a seasoned British agent, now disillusioned and on the brink of self-destruction, is sent to East Germany under the guise of a defector. He becomes entangled in a treacherous game of deception, where his true mission—to expose a high-ranking East German spy—unravels amid shifting loyalties and deadly traps.