The greatest fight scene in the MCU
For all the cosmic battles its a simple human fight.
Captain America fight in the elevator.
Are you limiting the "fight scene" to personal combat, or are big-ass battles included?
Because I've always loved the Battle of New York in the first Avengers film, it was visually spectacular, exciting, and each superhero's personality got a chance to shine (except Hawkeye, who doesn't shine no matter how much you polish him). It was full of wonderful character moments and moments of drama, my favorite may be the moment Captain American became the official leader of the Avengers. When the aliens arrived en masse and the whole team just stood there dumbstruck for a moment, and Rogers piped up with a plan of action, and that was the instant he became the team leader. It was a beautifully scripted moment, it showed someone taking charge not because he was a bully, not because he had the loudest voice or the most dominant personality, but because he was the one who'd studied strategy and tactics and he knew his shit, and everyone else respected that.