Canon just announced the RF 5.2mm F/2.8L Dual Fisheye Lens, a lens that lets you record 3D on the EOS R5, for immersive viewing on compatible VR head displays. Two 180° lenses capture stereoscopic imagery to a single image sensor.
This lens will be available in late December 2021 at an estimated retail price of $1999. See the Canon page for more info, and add the lens to your watchlist to track availability and pricing.