Here's the list of cameras that we have knowledge of suitability for Elgato Cam Link 4K:
https://www.elgato.com/en/gaming/cam-link/camera-check
Determining Compatibility For Unlisted Cameras
If your camera is not listed as a compatible camera on this list, then we will have to determine if this camera will work with the Elgato Cam Link 4K.
For any camera to work correctly you will need to have no overlays applied on the camera, because these menus and displays will be in the end recording. This is called Clean HDMI Output.
Additionally, you will have to have an unlimited run time (referring to your battery life) to make sure you will have an optimal amount of time to stream or record your video.
Here is a link that shows a few good ways to test your camera:
https://help.elgato.com/hc/en-us/articles/360028243051-Cam-Link-4K-Is-Your-Camera-Compatible-
You may also want to check the manual to the camera to see if you have the abilities listed previously.
You may also want to reach out to the manufacturer of the camera if you are having some trouble finding information about the camera itself.
System Requirements
Lastly, and probably the most important, you should verify that your computer meets the minimum system requirements needed to run the Elgato Cam Link 4K. Here are those requirements:
https://help.elgato.com/hc/en-us/articles/360028241671-Cam-Link-4K-System-Requirements