Microsoft added a pretty major feature to the Xbox One with the Summer Update, and that is support for Background Music. This feature isn’t enabled by default for all apps that can play music – instead, developers will need to add support for this feature to their apps.
For example, Groove Music and Pandora already support Background Music on the Xbox One. Today, iHeartRadio has updated their app on Xbox One with support for background audio.
Update the app from Xbox Store to start enjoying this feature.