The third-generation Apple TV (the set-top box) is losing support for the CBS All Access channel, as noted by MacRumors. It and the YouTube channel will both disappear next month.
A note to CBS All Access subscribers read: “We wanted to let you know that starting March 4, 2021, CBS All Access will no longer be available on this device [the third gen AppleTV]. On March 4, CBS All Access will become Paramount+. You can watch Paramount+ on Apple TV 4K, Apple TV HD, iPhone, or iPad. With AirPlay, you can also stream Paramount+ from your iOS device directly to any Apple TV (3rd generation or later) or AirPlay 2-compatible smart TV. For more information, go to help.cbs.com.