Canon 1D X II has a 20.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Dual DIGIC 6+ processor. On the other hand, Leica SL has a 24.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Maestro II processor.
Another difference between these two cameras is that Leica SL's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the 1D X MII and SL sensor size comparison.
Canon 1D X II and Leica SL have sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Canon 1D X II has 20% larger pixel area compared to Leica SL, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.