It's a typical question and unfortunately most candidates do not prepare accordingly for the PEI, even though it contributes to ~50% of the overall evaluation - so I am glad that you are proactively tackling this topic!
Definitely, the McKinsey PEI is an interview format of it's own, and there are many many specifics to consider - it's not just talking 'something' about leadership etc.
In order to avoid copy/paste from other sources, you can find on my blog many short articles on the McKinsey PEI to get a much better understanding of this interivew format (https://pei.consulting-case-interviews.com/blog/). For a structured, complete guide to the McKinsey PEI I have summarized everything you need to know for PEI prep also in an ebook (https://pei.consulting-case-interviews.com/).
Hope that helps to get you started!