While Florence Pugh is one of the biggest stars in the Marvel Cinematic Universe today, we almost had a completely different scenario play out where she was never cast. Pugh plays Yelena Belova, Black Widow's sister, who was introduced in 2021's Black Widow starring Scarlett Johansson. She later reprised the role in Disney+'s Hawkeye and will don the white costume again in Thunderbolts. In an alternate universe, Saoirse Ronan would be playing the character.