The Canon EOS R Mark II is already in testing according to latest rumors on CR. This camera currently is testing by a small group of photographers. The official announcement of this camera is expected ahead of Photokina 2020 in May.
The Canon EOS R Mark II will coming after the high megapixel EOS RS which will be announced mostly like at CP+ 2020 in February. It will have similar design as Canon EOS RS. Specs of Canon EOS R Mark II will be available soon, stay tuned.