First: if you are still underneath 3 years / 36,000 miles: Seek warranty repair guidance from your local dealership.
If not, are you saying the vehicle starts and the radio, navigation system and heater does not work? Or nothing works?
RepairPal Certified shops can diagnose and repair your 2016 Cadillac Escalade. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.