The Canon 5DS and 5DS R were notable for offering 50-megapixel sensors at a time when that was an extremely high resolution for a full frame camera. Nowadays, 45-50 megapixels is much more common on higher-end camera bodies, with full frame options topping out at 61 megapixels. It looks like Canon plans to eclipse that figure by a significant amount with a new camera, however.
Canon Rumors is reporting that Canon has been planning a 75-megapixel RF mount mirrorless camera. There have long been rumors of such a camera being in the pipeline, and I would be very surprised if a model analogous to the 5DS R didn't eventually appear, perhaps an EOS R5S.
Canon's RF lenses have generally been turning in highly impressive performance, and most of them could definitely handle a bump in resolution just fine, plus retaking the resolution crown from the Sony a7R IV would give Canon some nice bragging rights. Considering the EOS R5 is really the do-it-all camera of the RF line, I am sure a more specialized body for things like landscapes and studio work has been under consideration for a long time, though I'm sure a lot of resources are being devoted to the upcoming EOS R1 flagship at the moment. Hopefully, we will hear more soon!