you play xbox 360 games on xbox one
On June 15, 2015, backward compatibility with supported Xbox 360 games became available to eligible Xbox Preview program users with a beta update to the Xbox One system software. The dashboard update containing backward compatibility was released publicly on November 12, 2015. The following is a list of all Xbox 360 games compatible with the Xbox One under this functionality.
List of Xbox 360 games compatible with Xbox One