In Canada we have really cold weather and heat pumps are used but only down to between -5C to -10C depending on the efficiency of your pump. If I tried to run my heat pump in really cold weather it would just never reach the desired temperature.

One option is to use a ground-source heat pump in that kind of situation, if you have enough land to dig or drill to install the exchanger pipes. Most places in Australia where I live are able to just use air source but I've seen ground source ones in Europe.

Some parts. But for a car sold in all 50 states a general heat pump isn't going to work.

Some areas can get down to -20F, even -40F in the winter and this is major metropolitan cities.

Perhaps this is a new type of heat pump or it sources heat waste energy within the car itself.