It's pretty much a given that Canon and Nikon will be coming out with professional mirrorless cameras in the next year or so, but lots of questions remain about what exactly the cameras will bring, including the lens mounts they'll use. A new patent from Canon gives us a bit of insight into their current development.
The lens appeared as a Japanese patent application (2018-077320) and is a 16-27mm f/2.8 model with a short back focal distance (the distance from the vertex of the rear element to the sensor), indicating it's for a mirrorless body. Furthermore, constant-aperture f/2.8 ultra-wide-angle zoom lenses tend to be professional-level glass, so it's indicative that Canon is taking their mirrorless development quite seriously and likely aiming for the professional segment. Nonetheless, we see many patents for lens designs that never make it to the market, and there's no guarantee that this specific patent will turn into a lens on store shelves. This is also does not necessarily indicate that Canon is dropping the EF mount for their upcoming mirrorless line, though it does indicate that they're at least exploring the possibility. One thing is for sure, though: Canon is getting quite serious about professional-level mirrorless, and that's good news for photographers.