In the re-release of "Avengers: Endgame" after the end credits Anthony Russo announces the post credit scene which in this case was a deleted scene. He mentioned that they loved that scene but it just had to be cut due to already long running time of the movie. So they were really happy to be able to include it in the movie this way - as a post credit scene.
In this scene we see:
Hulk saving some people from a fire in a high-rise and then receiving a phone call. When he answers the phone, he listens and then says "Steve?".
I did not get it AT ALL. What was so special about out? What does it mean? Why it was worth including in the movie?