Considering that her pre-Captain America: Civil War appearances include the likes of Iron Man 2, The Avengers, Captain America: The Winter Soldier and Avengers: Age of Ultron, that is potentially a lot of filling in that needs to be done, with ample opportunities for Black Widow to get into some action-packed espionage escapades.
Knowing the movie is set following the events of 2016’s Captain America: Civil War, audiences will get to see what Black Widow got up to during a time when superheroes have been outlawed.
Even just the events between Captain America: Civil War and Avengers: Infinity War have a lot of ground to cover.
At birth, the Black Widow, aka Natasha Romanova, is given to the KGB, which grooms her to become its ultimate operative.