Zoro will have / display CoC before / when fighting BB.
Let me phrase it first.
One thing people tend to forget that CoC is a 'worthy to be king' aura. That's why Luffy got it since he wanted to be king of pirates or destined to be.
It isn't coincidence that someone who has CoC is someone who has been leader of group. Roger, Shanks, WB, Doffy, Hancock, Luffy etc. One thing they need is a trigger button such as anger, sadness or anything that strong willed emotion.
Now why some 'second in command' people like Ray or Katakuri have CoC?
In Katakuri's case, he's the one who protect family from her angered mother. He's the one who to be said can lead BM pirates once BM died. He's the one who can unify people under him if somehow BM pirates broken to pieces.
And I think Ray got his CoC if not after/right before they got to Raftel. He must be realized at some point what the crew will be without Roger or once he knew Roger got illness.
On the other hand. What will Zoro do if somehow Luffy died or the crews are separated. Can he unify the members? And continue the journey? Hell no, He will be a lone wolf again.
What is Zoro's strong will? Being WSS? or being strongest? Yeah we know Zoro wanted to be WSS since long but he won't really chase it wholeheartedly if he didn't meet and promise Luffy and his defeat in Mihawk's hand forced him to be.
For now Zoro didn't show me 'worthy to be king' aura. Maybe once he learnt his blood or his clan that will be turning point of him. He realized he's capable of being king. He's already had potential to activate them tho.
I can be wrong.