Avengers: Infinity War, like other crossover films in the Marvel Cinematic Universe, is going to change the futures of the various characters involved. One of the big heroes showing up to save the world will be Doctor Stephen Strange, played once again by Benedict Cumberbatch and returning in full force for the first time since his solo movie in 2016. As the owner of the Eye of Agamotto, aka the Time Stone, Stephen's a high value target for Thanos and his quest for the Infinity Stones.
We know that Stephen will be roughed up by Ebony Maw, one of Thanos' children, to say the least, but everything else related to the magic-based hero is up in the air beyond that. Cumberbatch, for his part, has said that even he isn't really sure if there'll be a second solo film for him once Infinity War and its currently unnamed sequel have released. Scott Derickson, director of the original film, has ideas of what he wants to do for a hypothetical sequel (including a potential bad guy), but that's far from confirmation that a sequel has actually been green lit.
There's two possibilities at play here; on one hand, perhaps Marvel Studios is just playing things close to the chest and waiting to announce a new movie once Phase 4 arrives. There's also the possibility that Cumberbatch is being truthful and there really isn't a sequel in place. Assuming that there's not a second solo film in development, the future antics of the Sorcerer Supreme would be more than ideal for a television show.
Some may view the idea of Doctor Strange going from film to television in lieu of a sequel to be a downgrade, but that doesn't have to be the case. For better or worse, television has been giving its big screen brethren a run for its money, and if there's any superhero in the Marvel roster that would benefit from a TV show as opposed to a movie apart from Spider-Man or Daredevil, it would be Strange.
Marvel Studios could pitch it as "a deeper look into the adventures and world of the Sorcerer Supreme" so it looks less like a downgrade and more of an expansion of the magical elements the original film only teased at. The success of Legion and Westworld have made it clear that modern audiences aren't afraid of complex shows that get super weird. And if there's one thing that can agreed on for Doctor Strange the movie, it's that the visuals are appropriately trippy and dazzling for a man who is one of the greatest magic wielders on the planet. And television is the perfect place to further expand upon what the first movie only scratched the surface of.