I believe the seat heating and cooling controls have been combined into a single button. How that works is a great question and I've been looking for an answer. I checked the demo X5 manual in the driver's guide app and didn't find any details there.
Edit:
Check out
https://www.bmwblog.com/2018/09/27/t...-flawless-suv/ and look a few pictures down. It looks like it's one button and it's shown on the iDrive screen.