It looks like the 2009 Cadillac DTS was the first model year for the DTS to come standard with Bluetooth, but it’s designed to handle hands-free phone calls, so you wouldn’t have much luck streaming music from your phone.
However, if other factors make the DTS more appealing to you than other cars, the lack of Bluetooth as a built-in feature doesn’t necessarily have to be a dealbreaker. Here are a few options you could consider: