Canon News posted about a patent recently about actively cooling an RF mount camera with an adapter. In this patent, it's a cooling EF to RF adapter.
In Japan Patent Application 2019-186871 You can see the adapter and the flow of air from the adapter.
Canon News says:
The camera does have to be properly built to handle heat transfer from the sensor to the lens mount, but this is certainly something Canon could accomplish. One of the engineering problems that even Sony and others have is how to cool a sensor that is not fixed in place because of IBIS. Flexible heat transfer materials made of polymer do exist, so it's possible to cool the sensor directly even with IBIS.
I recently reported that new RF mount adapters were coming, but unfortunately, this wasn't one I had been told about.
Canon Rumors has been so ahead of the game
Canon should have made the R5 far bigger so it could handle the heat better.
They should have included fans and a far bigger heatsink. While they were making it bigger to better handle the heat, they could have put in built in NDs to make life more convenient for the video shooter.
Oh and with a bigger body to handle the heat better, they could have also put more buttons on the body so that you could change key video settings without having to go in to the menu i.e. dedicated buttons for ISO / shutter / FPS / peaking / zebras etc.
With a bigger body they could have also then had full size HDMI and better audio input abilities e.g. dual XLRs and on-body control for the audio levels etc.
With a bigger body, they could also probably have managed to come up with a solution for swapping out lens mounts easily so YouTuber bloggers could switch between EF and PL mounts for their Vlogs.
Finally they could have had a bigger screen and also larger EVF to make working in video far easier. In fact, they probably just should have removed all the photography features and weather-sealing of the R5 because it's clearly just compromising the video side of the camera.
If only such a camera existed in Canon's range for people that want to do video....
Definitely sarcasm. He's just describing the features of Canon's cinema line.
Whether Canon introduces a way to actively cool their EOS R series of cameras through a PL mount adapter or through a battery grip, this must certainly be something on their radar.