Canon has been rumored to announce a new Canon EOS R Pro mirrorless camera for a while. Nikkan Kogyo Shimbun now reports that a prototype of a new Canon EOS R Pro mirrorless camera already exists and the official release is expected in 2021 (Google translation):
"Canon will introduce the highest model of mirrorless camera using a 35mm full-size image sensor in 2021. The communication function between the camera body and the interchangeable lens will be higher than the high-priced “EOS R” released in October 2018. A prototype (prototype) has already been completed"
Via Digicame-info