Apparently Evans spoiled Anthony Mackie's promotion through some very MCU theatrics, part of which had convinced Mackie that a new version of Endgame's script he hadn't read was going to kill off Sam Wilson. As you'll read in this anecdote recalled below, that couldn't have been further from the truth:

No one was more surprised than Anthony Mackie that he was the new Captain America – mainly because he thought his character Sam Wilson was going to die in Avengers: Endgame.

Anthony Mackie didn't know what to expect when Chris Evans led him into his man cave a few years ago. Mackie, the current titular hero in the upcoming Captain America: Brave New World, revealed in a conversation with Fandango how he found out he'd be taking the shield from original star Chris Evans.

Anthony Mackie shared that he found out he'd be taking over Chris Evans' role as Captain America in the forthcoming installment, Captain America: Brave New World, from the Marvel star himself.