Is Canon EOS R5 C and Sigma EX 500mm f/4,5 HSM APO DG compatible?

Below you will find your chosen camera and lens. Click on the product name for more information.

Buy	Canon EOS R5 C Released: 2022 Type: Mirrorless Sensor: Full frame 45 Megapixels 8192 x 5464 pixels
Buy	Sigma EX 500mm f/4,5 HSM APO DG Released: 2005 Telephoto Lens (prime) Focal Length: 500 mm Aperture: f/4,5

Can you combine these two?

This is the short answer:

No! This combination is not compatible

The camera and lens you have chosen cannot be combined. Here is a longer answer:

Not a lens for the Canon EOS R-system

This Canon EOR R camera and this Sigma lens is not compatible. For this camera, you can only use lenses that are constructed to work with the Canon EOS R-system. If you are using the Canon Lens Mount Adapter EF-EOS R you can also use other and older Canon EF, EF-S, MP-E and TS-E lenses.