The Guardians of the Multiverse defeated Ultron in the season finale of What If...? earlier this week. Black Widow, who was brought back for episodes 8 and 9 following her terrible death in the third episode, was at the forefront of the assault on the A.I. In the conclusion, Black Widow shoots Ultron with an arrow laced with a virus. The Watcher then transports Lake Bell's Natasha Romanoff into a realm where the Avengers' Black Widow has died.
A.C. Bradley, the chief writer of What If...?, spoke with Variety about Black Widow's future in the Marvel Cinematic Realm, foreshadowing how Natasha Romanoff might return to the universe where she battles Loki.
Bradley went on to explore the significance of where Black Widow was put in the MCU, as well as tease the MCU's plans for the character, but nothing definitive has been announced as of yet.
It's still unclear how much of an impact What If...? will have on the greater MCU. It wouldn't be strange if any of the characters from the program appeared in films like Spider-Man: No Way Home or Doctor Strange and the Multiverse of Madness, especially because the multiverse is already such a big part of the franchise.