When John Walker was named the new Captain America in the 80s, he also had a sidekick in the form of Battlestar. Originally called Bucky before the name was changed to Battlestar, Lemar Hoskins was the sidekick to John Walker’s Cap during that storyline in the comics.
With John Walker being named the new Cap in the MCU as part of the storyline in The Falcon and The Winter Soldier, it’d make a lot of sense to introduce Lemar Hoskins to the MCU, and a new set photo released by Sebastian Stan seems to confirm that’s going to happen:
You see both Stan and Anthony Mackie there, with giant parkas covering their costumes (but you can see Mackie’s boots) and between them you can see Wyatt Russell in his US Agent costume and someone next to him who appears to have a giant star on his chest. Unless the shirt he was wearing at that day just happens to have a stylized giant star on it, this could be confirmation that Battlestar will be joining the John Walker Captain America in The Falcon and The Winter Solider.