Tony Stark dies when the bomb explodes, Steve Rogers dies when the plane crashes, Bruce Banner dies from gamma radiation exposure, Wanda and Pietro die when the bomb explodes, Loki dies when he falls into the void, Clint kills Natasha, Bucky doesn't fall from the train but lives to old age, Thor remains forever stripped of his powers and banished on earth, Thanos dies with the rest of his planet, Nick Fury gets executed as a spy during the Cold War, Yon-Rogg shoots and kills Carol before she shoots the energy core, Odin never has Hela, Stephen Strange dies in the car accident, Marc Spector drowns instead of his brother, the people that killed Shang-Chi's mother find him and kill him too, Peggy Carter was never allowed into the military and didn't meet Steve, because Tony and Bruce are dead, Ultron is never created, and Sylvie is left alone by the TVA. We pretty much have no MCU.