What to wear for Black Widow: Because who doesn't want to be a badass woman Avenger, am I right? To transform into Black Widow, an all-white suit complete with fighting gear will do the trick. Don't forget about Black Widow's iconic red hair, either.
What to wear for Yelena: Yelena and Black Widow essentially have the same suits, except Yelena's outfit is more army-like, with a green vest and black gloves.