For the Mavs it is pretty simple. They want to win now, and Caruso fits into that. As good as Exum has been playing off of Luka and Kai, Caruso would bring everything he does plus more. He is a great shooter and defender, and plays extremely well off ball, keeping the offense flowing. He can also be a secondary ball handler when one of Kyrie/Luka sits.

The Bulls get a young prospect who has shown flashes but hasn't thrived in the iso heavy offense of Dallas, but could thrive with less pressure/more opportunity. They also acquire an unprotected first round pick to help their rebuild get going.