That's not gonna happen. Per IMDB, Emily VanCamp isn't listed in the cast for infinity war.
IMHO, the whole Sharon romance was shoehorned in. No work was done to set it up. the last time Steve saw her in Cap2, he was frostily calling her "neighbor." And at the beginning of Cap3, Steve didn't even know where she was or that she was now CIA. Never mind the fact that she was Peggy's (grand?) niece. That kiss was simply a big no homo.