In which film did Black Widow first appear?

Black Widow first appeared in the Marvel Cinematic Universe in Iron Man 2. Scarlett Johansson plays Natasha Romanoff, who is introduced undercover as Natalie Rushman, Tony Stark's new assistant.

During the film, Romanoff is revealed to be a highly trained S.H.I.E.L.D. agent working under Nick Fury. Her mission involves evaluating Stark and monitoring the growing threat from Ivan Vanko and Justin Hammer. She eventually reveals her combat skills during the assault on Hammer's facility, making her MCU debut as both a spy and a formidable superhero.

The 2021 film Black Widow is not her first MCU appearance; it is a later-released standalone movie set mainly between Captain America: Civil War and Avengers: Infinity War. Likewise, The Avengers follows Iron Man 2 and expands Romanoff's role within the team. Her comics counterpart first appeared in Tales of Suspense #52 in 1964.