I need help! Where have I seen this scene?

So… I have a Marvel- scene in my head, but I have no idea where it comes from. Post credit? Ending? Trailer? No idea. I hope someone here can point me in the right direction. The scene is post war/post apocalyptic. Some of the avengers are standing outside a big city. Evertyhing around them is in ruins. There might og might not be someone or something coming up from behind. The avengers decide its time to charge and they start moving towards the city line. It feels like we are in a different timeline or alternate universe.