A glimmering of thought

Cable & Deadpool is hilarious for the opposite reason; they are completely opposite characters. They have history too. I believe Deadpool was actually introduced as a merc sent to kill Cable. I would absolutely start with the first few Cable & Deadpool graphics/collections. Not only are they great, but they encompass an ongoing storyline, so you lose a lot if you don't read them in order. Volume 1 is called If Looks Could Kill and I think it's just right. It is about both of them, so you will get to know a lot about Cable as well.