Natasha Romanoff will cross hairs with her famous Black Widow successor, Yelena in the upcoming prequel. In the comics, the two Russian women start off as enemies before reconciling as allies later. Yelena is also apart of a superhero team called the Thunderbolts, which is mostly made up of reformed villians, also including Baron Zemo, Deadpool and Winter Soldier.
Article source: https://www.cinemablend.com/news/2481400/looks-like-black-widow-will-feature-another-familiar-mcu-face