Hayden Christensen isn't done playing Darth Vader. According to The Hollywood Reporter he will reprise his role as the Sith Lord for the Disney+ series Ahsoka. Rosario Dawson will play Ahsoka Tano. She also appeared in The Mandalorian's second season. This will be the first appearance of Ahsoka Tano in live-action Star Wars shows. Before that Ahsoka was only seen in animated Star Wars entries.
The story of the live-action series has not been revealed by Lucasfilm and Disney. According to The Hollywood Reporter, it will be set five years after Return of the Jedi. This is similar to The Mandalorian. It's not surprising that Vader will appear in a show about Ahsoka, considering she was Anakin Skywalkers padawan. It's not clear how Vader's character will fit in Ahsoka’s story. Also, flashbacks and Force ghosts aren't possible.
Dave Filoni, a veteran of several Star Wars projects, will be writing the story and serving as executive producer alongside Jon Favreau. Production will begin in 2022. However, fans will be able to see Christensen as Vader in Ewan McGregor’s Obi-Wan Kenobi which will debut in the first half of next year.