The Black Widow movie isn't an origin story because Scarlett Johansson doesn't want one. As a member of the original Avengers, Natasha Romanoff has been in the MCU since Phase 1. But unlike most of his male counterparts, she didn't have her solo film until Phase 4, and to make it worse, when the character's already dead in the franchise.

Not much is known about Nat's backstory, although there have been hints about where she came from peppered throughout the Infinity Saga. Before becoming an Avenger, she was originally a Russian spy brought in to be one of Nick Fury's most trusted operatives back when S.H.I.E.L.D. was still functional. While she doesn't have any superpowers, she proved to be extremely instrumental in Earth's Mightiest Heroes' biggest missions. On the heels of Thanos' snap in Avengers: Infinity War, she kept the Avengers semi-functional, checking in with their various allies around the galaxy. Eager to see their fellow heroes return from being decimated, Nat sacrificed her life on Vormir in exchange for the Soul Stone.

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Despite her death in Endgame, Marvel Studios is hoping to properly wrap up the character's arc in Cate Shortland's Black Widow. Instead of fully tackling Nat's history, the film will be set in between Captain America: Civil War and Avengers: Infinity War as she reunites with her Russian "family." According to Johansson during a set visit attended by Screen Rant and along a group of reporters, this seems to be a great jumping point for her standalone story as she didn't want to go further back in time but look forward into the future. Johansson said:

Post-Civil War felt like a good time to start. We never intended on doing an origin story, I never wanted to do an origin story because I just didn’t want to go back that [far], I wanted to move forward- even though we are going back, but it’ll make sense when you see it.

Black Widow and her vision as she aims a gun in the Red Room in Avengers: Age of Ultron

Just because the primary narrative for Black Widow is set amidst the events of MCU Phase 3, the Black Widow movie will jump through other points in time. The trailers have teased the appearance of a young Nat in what appears to be her initial separation from her family. Milla Jovovich's daughter, Ever, is confirmed to play this version of the Avenger. There's also the shot of a significantly younger Thunderbolt Ross, which means that his cameo in the upcoming blockbuster will precede his involvement in The Incredible Hulk. Given all this, it's still possible that Black Widow will complete Nat's story in the MCU through non-linear storytelling.

Arguably the most interesting part of Johansson's quote, however, is her tease about how Black Widow somehow moves forward. Nat is currently dead in the MCU, hence why the standalone film is a period piece. Given this, it's curious what she means by the film moving her story forward. Resurrecting the character is almost out of the question as it could cheapen her already controversial death. Otherwise, she might be referring to Yelena being set up to be the next hero to take on the moniker in the MCU after Black Widow.

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