Call of Duty: Modern Warfare 2 is now backwards-compatible on Xbox One. So if you own a copy of the game on Xbox 360 you can play it on your Xbox One.
This video shows some guy playing Modern Warfare 2 on his Xbox One. And even though he’s usually a PC gamer, he does pretty well too.
One of the problems of being a console gamer is the lack of backwards compatibility. Which means you can’t play your old games on your new console.
However, this is one area in which Microsoft is beating Sony, as the Xbox One is capable of playing many older titles, as opposed to the PlayStation 4.