Went back and watched a lot more of him. Defending is a big question mark in a 4 man defence.
But attacking wise, he is really comfortable on the ball. Really comfortable being pressed up against the touch line. I can't say there are many more technical RBs around the world. Short passing is accurate, crossing is dangerous.
He's above 40M in attack, I think. His attack style is actually similar to Alex Sandro but I think in most facets he is just a touch quicker and smoother. A little better playing quick combinations. In form Alex Sandro could dribble around for a while, more than Cancelo, but Cancelo has a little more bite and directness I find.
Again, defensively who knows. Dives in like Cuadrado.