u/Kyoshaka

So I saw that xbox has a sale for the older CODS out for 10 dollars right now and I was tempted to get them bit couldn't find the orginal on it. I Google, bing, a look everywhere I could on reddit and everyone claims it's on the store but I can't find it in the store on my xbox. Is it an online (not on the xbox) store only or am I just missing it?