The Marvel Cinematic Universe is a franchise consisting of film and television adaptations of Marvel Comics publications produced by Marvel Studios. The franchise is notable for being the first superhero film franchise to have characters and plot points from different titles crossover.
Natasha Romanoff is the comics and MCU version of Black Widow - a superhero trained originally as a Russian assassin and spy and later recruited into SHIELD and the Avengers. She is portrayed by Scarlett Johansson, who has proved incredibly popular in the role. Many fans have pushed for the release of a Black Widow solo film, but so far, the character has appeared only as a supporting character in Iron Man 2, The Avengers, Captain America: The Winter Soldier, Avengers: Age of Ultron, and Captain America: Civil War.