In a recent interview with Empire, the director Cate Shortland confirmed that the Scarlett Johansson's Natasha Romanoff will be handing her baton over to Florence Pugh's Yelena Belova as her new successor during the film much like how Steve Rogers passed the mantle of Captain America to Sam Wilson.
Here is Cate Shortland's statement in the article:
“[Kevin Feige] realised that the audience would expect an origin story so, of course, we went in the opposite direction,” Shortland tells Empire. “And we didn’t know how great Florence Pugh would be. We knew she would be great, but we didn’t know how great. Scarlett is so gracious, like, ‘Oh, I’m handing her the baton.’ So it’s going to propel another female storyline.”
https://www.empireonline.com/movies...-florence-pugh-says-cate-shortland-exclusive/
To be honest, I knew there would be someone to succeed Natasha and it will be a huge waste if Marvel Studios do not keep Florence Pugh on for future MCU projects considering that she is a talented and rising actress in the film scene.