Since you did not address personal fit (especially a severely underestimated topic for McKinsey interviews with the proprietory Personal Experience Interview format), I assume you are interested only in the case portion.
Main question in the first place is which cases and which interviewers you had - if it's simplified and shallow cases like many to be found on PrepLounge, and if you had peers as interview partners .. I am not sure if you are well prepared at all. You would be surprised how many candidates are having a reality-check session with me to find out how many details they never thought about before, and sometimes which fundamental mistakes they made looking innocently from candidate's perspective but being immediately a red flag for interviewers. Just a warning, in case that's your situation.
So maybe you can add some more details to your question to answer for your specific situation..
Hope this helps - if so, please be so kind and give it a thumbs-up with the green upvote button!