Do you need an “Xbox one X” to play Left 4 Dead 2 or can it be done on an “Xbox one S”?

I have an Xbox One S. It does not allow me to download L4D2 in the game store. But online, I am able to purchase it. I tried downloading the free demo to see if it would show up on my console and it did not. Does that mean L4D2 is not backwards compatible with the Xbox One S?

Edit: Thanks for the responses!