Apple has (finally) introduced the new Apple TV 4K with support for both 4K and High Dynamic Range (HDR).
With Apple TV 4K, viewers can enjoy a growing selection of 4K HDR movies on iTunes. iTunes users will get automatic upgrades of HD titles in their existing iTunes library to 4K HDR versions when they become available. Apple TV 4K will also offer 4K HDR content from video services, including Netflix and Amazon Prime Video, coming soon.
Source: Apple TV finally gets 4K and HDR