This policy details how the configuration and pairing system will work and the option to share keys through the Messages app. It also clarifies that Apple will not obtain any information about the vehicle, or its use :
According to the screenshots found in iOS 14, it seems that Apple has already reached an agreement with the manufacturer BMW for the first compatibilities. It remains to be seen if, from the discovery of these screenshots until the date of the presentation, Apple will have closed further deals.
At AppleEverything we know about iOS 14 and iPad 14: Home screen enhancements, widgets, keychain, Maps, CarKey and more
With all this information it is clear that the launch of CarKey is closer than we thought, being possible that this functionality will be presented in the WWDC next Monday.