There is a lot of evidence, long term studies, showing they do not do cancer. So the question is why are they listed as a possible cause? It invalidates the entire list. My car keys may well "possibly" cause cancer if the bar is so low.
The specific item that is on the IARC Group 2B ("possibly carcinogenic") is "radiofrequency electromagnetic fields", which includes exposures due to cell phone use-- cell phone radiation specifically is not classified.
So, if your car has keyless entry, your car keys would technically also be on the list.
