Can anybody let me know of the cheapest way to add CarPlay to a 2016 XJ with in control pro?

It doesn’t have to be wireless.

Thanks!

 

Cheapest is probably an Android overlay screen. If you're in the US, I have one that I used for a few months that I'd make you a deal on.
Otherwise you'd retrofit a 2018-19 ICTP screen and update the car to be able to have factory integration.
The big thread on the retrofit here has mention of enabling the smart phone pack with the 8" screen if you're on the right (old) version, but that would take some SDD knowledge and manipulation.