Originally Posted by
Relugus
Wanda and Vision will be retired post-Endgame. This is heavily foreshadowed in Infinity War:
"We both made promises."
"But not to each other."
The promises they made were of course to Tony and Steve, which was the only thing preventing them seeking a new life together.
Also foreshadowed is White Vision, but you can't make a whole series about emotionless White Vision, so I buy the rumour that Wanda attempts to restore Vision leading to the shenanigans that will drive the series.
They can use a variety of sources and elements for this series:
Vision & Scarlet Witch (attempt at normal life)
Tom King's Vision (Vibranium Piano, social commentary, Everbloom, tone)
Avengers: Nights of Wundagore (Wundagore, Chthon,
Mystic Arcana (backstory reveal tying into the Stark bomb)
Doctor Strange: Birth of Chthon (perfect for the climax, this story has always been more suited to Wanda than Strange, with Vision being the "pure soul" Wanda draws upon instead of Victoria Montessi).
House of M (reality warping elements, I can see them using the "lego" effect, but none of the plot).
What Feige said does match with the 4chan leaks (as do Falcon & Winter Soldier). Chaos Magic and Wanda's emotions fusing and creating a kind of "WandaVision", so the title tells us who the protags are, and also alludes to Wanda's powers being a core element of the show.