It appears the first full images of the actual 5D Mark IV body have been leaked. There’s a couple of visual changes between it and its predecessor. The most obvious being that the “Mark XX” badge has been moved. This has allowed Canon to move the shutter release cable socket around to the front.
The eagle eyed amongst you may also spot that the microphone grill seems to have disappeared. It doesn’t appear on the other photos, though. Not that an internal microphone is all that great, but I do wonder how good the sound will be for syncing purposes.