Hawkeye episode 5 answers what happened to Black Widow's sister Yelena Belova during the blip

Hawkeye episode 5 gives audiences two things -- Kate Bishop and Yelena Belova's (Florence Pugh) entertaining banter and the answer to a very important question. What happened to Yelena Belova during the Blip? After Thanos' snap, half the population had disappeared. This included Bucky Barnes (Winter Soldier), Drax, Groot, Jane Foster, Mantis, Wanda Maximoff, Peter Quill, Hank Pym, and Shuri among others. Yelena Belova and the fate of other members of Natasha's family were not addressed. 

After the release of the Black Widow standalone film, fans had a question about Natasha Romanoff's family's fate during the Blip. Was she desperate to undo Thanos' snap because her family had disappeared leaving her all alone? The answer is never clarified in the film. Even the post-credit scene of Black Widow that featured a conversation between Yelena Belenov and Contessa Valentina Allegra de la Fontaine (Julia Louis-Dreyfus) takes place after the events of the Blip. 

The episode revealed that Yelena was among the victims who had disappeared after the snap. The sisters do not get to meet after the events that take place in the film. The absence of closure in their relationship fuels Yelena's need for revenge further. It also pushes Clint Barton to the corner as he is suffering from a deep sense of guilt over Natasha's death. 

In Avengers: Endgame, the two visit Red Skull to procure the soul stone. They have to choose to sacrifice a soul for a stone, just as Thanos had done in the past. Natasha chooses to sacrifice herself despite opposition from Clint and he relives this horror every day in her absence.

In fact, Clint Barton's struggle with his guilt is what draws a distance between him and Kate Bishop in Hawkeye as well. As the show nears its finale, we will see how Yelena's appearance will change Clint Barton and the direction of his life as Hawkeye as well.