Trivia: When Pietro says he'll help the twins maximise their candy acquisition, one twin says "Kick-ass!" and Wanda repeats to herself "kick-ass." Both Aaron Taylor-Johnson, who played Pietro in Avengers: Age of Ultron, and Evan Peters, who plays "Pietro" in WandaVision and the recent X-Men films, both starred in Kick-Ass.
Trivia: This is the first Marvel show that Marvel Studios President Kevin Feige considers to be canonically set in the Marvel Cinematic Universe. Although other shows such as Agents of S.H.I.E.L. D, Inhumans, Daredevil, Jessica Jones, Luke Cage, Iron Fist, The Punisher, Runaways, and Helstrom were said to be set in the MCU, Feige had no direct involvement or say-so on their direction, and therefore doesn't consider them to be canon. He even stated that he considers Phil Coulson to still be dead, despite being the main character in Agents of S.H.I.E.L.D.
Trivia: Pietro makes various hellish references which tie into fan theories that what's going on in Wandavision is the work of a demon, quite possibly Mephisto: "Unleash hell, demon-spawn" and "damn it, if Westview New Jersey isn't charming as hell."