I went as far as the second round interview for McKinsey. The first round was their standard assessment test with two group case studies at the end. I was told that the outcome of the first round interview was solely based on the assessment test. The group case studies were actually meant for the interviewees to get a sense of how the later individual case interviews would be (which was more than helpful for my case). The assessment test was very similar to the online sample test they post on the website. The only suggestion I can give is to practice your math and learn about some of the various sales definitions. The second round interview for me was in Boston. I had two 1:1 interviews, which included both personality fit portion and case study portion. The two fit questions I got were: 1. Give me one instance that shows your leadership skills. 2. Give me one example that you resolved a conflict within a team.