The MCU introduced Wanda Maximoff as a native of the fictional Eastern European country of Sokovia in Avengers: Age of Ultron. It is unclear if this is the same country Olsen is referring to during the interview. There are several reasons why Olsen might have not named Sokovia specifically, but this also opens up the possibility that WandaVision will show where she originally came from before. Wanda has a convoluted history in Marvel’s comics, to say the least, but she is a native of Serbia originally. Wanda and her brother Pietro Maximoff, aka Quicksilver, were unknowingly kidnapped as children though. It is possible that WandaVision could reveal a similar backstory for Wanda.
Even if WandaVision doesn’t add a new wrinkle to where Wanda was born, there are plenty of fans expecting the show to retcon her backstory in other ways. For most of her comic history, Scarlet Witch was thought to be a mutant and the daughter of Magneto. The MCU couldn’t use this backstory when Wanda debuted in Avengers: Age of Ultron due to Fox holding the rights to all mutants, but one of the most popular WandaVision theories is that this will change in Phase 4. With the marketing for the show including plenty of Easter eggs to a loose House of M story, Scarlet Witch coming from another Eastern European country could be the beginning of the reveal that she’s actually a mutant in the MCU after all.
Originally from https://screenrant.com/wandavision-scarlet-wtich-origin-eastern-europe-sokovia/