Published sources rarely list the drag coefficient for vehicles like the Escalade. Automakers don't typically release this data to the general public, and independent testing is not always consistent.
Therefore, you're unlikely to find a precise number. If you need this figure for a specific calculation, you'll have to make a reasonable estimation based on similar vehicles or use a general range for large SUVs. Expect the Cd to be somewhere in the range of 0.38 to 0.42, though this is just an approximation.