The future of Canon cine is RF mount.
It does not take an expert to realize Canon will eventually be moving its popular cine cameras to a native RF mount. When? We don't really know, but it's going to happen. That said, another camera, which has been in the No Film School news feed often, is the RED Komodo. The 6K Super 35mm camera has a native RF mount and will eventually support it with phase detection autofocus. It's uncertain when that will happen, but when Komodo does start shipping, RED will be including an EF to RF adapter.
Duclos Lenses, a well-known specialty lens shop, is getting ahead of the curve by offering a conversion for Fujinon's popular MK cine zoom lenses that modifies the housing with an RF mount.
The MK lenses, which come in in 18-55mm T2.9 or 50-135mm T2.9, are noteworthy for Komodo as they're capable of covering the Super 35mm format. Duclos mentions the conversion does not affect the manufacturer's warranty and is non-destructive. Meaning, all the lens features like back focus and macro functions are fully functioning. The materials used for the conversion are manufactured from aerospace-grade billet aluminum and are anodized to withstand daily production use.
Current MK owners will be able to get the conversion done for $495. If you buy them new from Duclos and want the conversion, they'll cut you a deal at $405. Expect the converted lenses to start shipping mid-September.