The CBC Gem app is not available on older generation Apple TVs which do not have access to the Apple TV app store.
For those with older model Apple TVs, you can still AirPlay our content from an iPhone or iPad.
Which Apple TV do I have?
You can identify older Apple TVs (where the Gem app cannot be installed), by their remote.
The older models have a silver remote control with 2 buttons and a directional pad.
Newer Apple TVs (where the Gem app can be installed) will come with a first or second-generation Siri remote. The first-generation Siri remote is black with a built-in touchpad and six buttons, and the second-generation Siri remote is silver with a directional pad and 6 buttons. and a directional pad. 
The only way to watch CBC Gem on these older models Apple TVs would be by using the AirPlay functionality. Please note that this will require an iPad or iPhone which already has the Gem app installed.
Using an iPhone or iPad
1. Open the CBC Gem app on your iOS device and select the content you wish to play.
2. Tap or on the screen to bring up the video controls.
3. Tap on the Airplay icon in the bottom right corner of the player window and then select the device you want to AirPlay to.
If you don’t see your Airplay-enabled device try connecting your host device and Apple TV to the same Wi-Fi network. Also check that you have the latest software installed on your devices.
Please note - older model Apple TVs are not designed to handle streams running at 1080p. If you are using AirPlay via the Gem app, you may experience streaming issues with CBC News Network which streams at a max of 1080p.
Our app automatically adjusts streaming quality depending on available bandwidth. However, if you are on a fast, steady connection, News Network will be presented at full 1080p. Therefore AirPlay may not be able to handle the stream properly.
AirPlay is also available on select LG and Samsung Smart TVs produced after 2018.
You can read more about which LG TVs are compatible here
You can read more about which Samsung TVs are compatible here
For additional AirPlay information, please visit the following Apple help article: https://support.apple.com/en-ca/HT204291