Taking inspiration from the comic books of the same name, each episode explores a pivotal moment from the Marvel Cinematic Universe and turns it on its head, leading the audience into uncharted territory.Source: TMDb
Currently, you can only stream What If...? on Disney+ in the United States.
Unfortunately, you cannot buy or rent What If...? on any of the streaming services in the United States at the moment.
What If...? was released this year (2021).