Christopher Markus and Stephen McFeely were clearly kicking around a lot of ideas for both Avengers: Infinity War and Endgame that ultimately never came to fruition, and one of them revolved around Wanda (Elizabeth Olsen) surviving Thanos' "snap."
During tonight's Quarantine Watch Party, the writers were asked if any of the heroes that were willed out of existence at the end of Infinity War were originally going stick around for the follow-up, and Markus revealed that there are "whole drafts" featuring Scarlet Witch going on a road trip with Rocket Raccoon!
Apparently, this plot thread was dropped because after everything that happened with Wanda and Vision in the previous film, it felt like "wheel spinning." Markus doesn't elaborate, but as fun as spending time with this unlikely duo would no doubt have been, with so much going on in this movie it's not hard to imagine it ultimately being seen as superfluous.
The movie has just finished, so be sure to check back for more tidbits from Markus and McFeely.