Kaido wondering if Zoro can use CoC doesn't equal to Zoro applying CoC infusion to his attack.
He didn't sense anything, he looks at the wound he received and assumes the same thing was used as last time he received such a wound.
Every time Zoro used aCoC, it was clearly visible and there is nothing during DeadMan's Game which literally has a panel focused on Haki. As I said, wishful thinking with 0 evidence. Also, haki oozing out of Zoro =/= coating attacks with it. Yall are jumping onto this because you don't wanna admit that Zoro scores feats like that with far more ease than monsters on PK's level.