A German YouTube channel recently published a video featuring a blurred, apperently new camera that is supposed to be announed next week:
Both Nikon and Canon are expected to announce new video-oriented camera models next week:
Next Nikon announcement is rumored for September 10th (Nikon Zr video-oriented camera?)
Canon EOS C50 full-frame cinema camera coming on September 9th?
There is also the possibility of a new DJI mirrorless camera, but those rumors have been circulating for over 6 years now without any substantial leak or proof:
The DJI camera rumors are nothing new really, TTartisan is also working on a new camera
Rumors: DJI coming with a mirrorless camera that looks like the Hasselblad X1D
Screenshots from this YouTube video