Pricing was not announced.
The CT6 will make its world debut at the 2015 New York Auto Show.
"The streaming video is a significant enhancement for the luxury customer interested in purposeful technology," said Travis Hester, Cadillac CT6 executive chief engineer, in a statement.
The technology boosts the driver's field of view, eliminating any rear seat, rear pillar or passenger obstructions.
Drivers can disable the streaming video by flipping the toggle on the underside of the mirror.
The in-mirror display is combined with a high-definition camera designed to enhance rearview lane width and maximize low-light situations, GM said.
GM said the innovation has been awarded 10 patents.
Edmunds says: With technology like this, traditional blind spots may be a thing of the past.