Warning — This article contains spoilers for WandaVision.
The inclusion of Darcy Lewis in WandaVision as a supporting character was rather baffling when it was first announced. After all, Lewis was just Jane Foster's intern in Thor and Thor: The Dark World. The idea of her working closely with S.W.O.R.D. left fans wondering what she could offer them since, again, the last time audiences saw her she was an intern with her own intern.
Head writer Jac Schaeffer said that Kat Dennings' Darcy Lewis and Randall Park's Jimmy Woo's inclusion is partially influenced by their past work on sitcoms like 2 Broke Girls and Fresh Off the Boat. One rumor pointed to Darcy Lewis helping S.W.O.R.D. with the restoration of Vision from when he was destroyed in Avengers: Infinity War.
However, a recent press kit release for WandaVision has finally given more context to Darcy working with S.W.O.R.D. as she's moved up in the world.
In an enormous media kit release for WandaVision, a production brief was released with it, giving a ton of behind-the-scene information for WandaVision. This includes backstory on some characters like Jimmy Woo and Darcy Lewis:
“She's gone on to become Dr. Darcy Lewis now...So, she’s a real expert in her field.”
Lewis is joined by Jimmy Woo who, together, “have a mystery to solve,” with Schaeffer adding that “They have so many questions and no answers.”
WHAT THIS MEANS
It seems like Lewis has finally graduated and earned her doctorate, presumably, in political science at Culver University. Again, why S.W.O.R.D. would need someone with experience in political science is still a mystery, but it could have to do with the environment that Wanda has created in her literal bubble.
It could be that Lewis is acting as a consultant for agents who attempt to enter WestView and how to interact with the people in it, especially Wanda and Vision.
Lewis could have also been brought on simply because she's two-degrees from knowing an Avenger like Thor. Since Wanda and Vision were Avengers, perhaps S.W.O.R.D. was simply desperate for any help in communicating with the two super-powered beings.