President Ross lays flowers at the grave of his wife which reads, Karen Lee Ross. In the comics, Karen Ross was introduced in 2011's "Hulk" (vol. 2) #41 as Thaddeus Ross' wife who died of cancer when his daughter Betty Ross was 12. The filmmakers gave Karen Ross the middle or maiden name Lee to honor the late Stan Lee. The flower arrangement includes a cherry blossom branch.
Sidewinder was added to the film during the reshoots.
Leila Taylor, played by Xosha Roquemore, is President Ross' Secret Service Agent and Sam Wilson's contact in the film. In the comics, Leila Taylor was a long-time romantic interest and confidant to Sam Wilson who was introduced in "Captain America and The Falcon" (June 1971) Issue #139. Leila eventually broke up with Sam and ended up working as a reporter who exposed drug smuggling.
The final act of the film is set in Washington, D.C., noted for its cherry trees. Director Julius Onah had vivid memories of the cherry blossoms from having lived near D.C. in Arlington, Virginia, as a child. To him, they aligned with the film's themes of empathy, since they were historically gifted from Japan as a sign of friendship.
Commander Dennis Dunphy, played by William Mark McCullough, is a U.S. Navy SEALs commander and ally to Sam Wilson. In the comics, Dennis Dunphy is an off & on superhero ally of Captain America called D-Man or Demolition Man.