In the comics, Bucky has a complicated romantic history with the MCU’s original Black Widow, Natasha Romanoff (Scarlett Johansson), who was Yelena’s sister and Alexei’s adopted daughter.
With the upcoming release of Thunderbolts*, I'm feeling the loss of a cut Black Widow storyline that would've added to Bucky's next appearance.
In Marvel Comics, Bucky Barnes had a closer connection to the Red Room and Black Widow than the MCU lets you think.