MIAMI — The short take on Cadillac’s new XT6 crossover SUV: It’s like the XT5 that I recently reviewed, but, as you may deduce from the alpha-numeric tag, a bit bigger. Perhaps you want more details. The Cadillac XT6 is a new vehicle for 2020 and completes the trio of crossover SUVs that replaced the SRX in the company’s portfolio.