Back to Duncan, who wants to know if the Thane of Cawdor is dead.
He is, and he confessed to being a traitor right before he died.
Whew. Glad that's settled.
Macbeth, Banquo, Ross, and Angus then meet the King. The King is grateful; Macbeth and Banquo pledge their loyalty; group hugs all around.
The King announces that his son Malcolm will be named Prince of Cumberland, which is the last stop before being King of Scotland.
They'll all celebrate the good news at Macbeth's place.
Macbeth trots off, thinking (well, saying, since this is a play) that Malcolm is all that stands in the way of his kingship. He's thinking naughty thoughts again and hopes nobody can tell that he's got "black and deep desires."
Get the scoop on this scene from its two major players in this interview with Macbeth and Duncan.