I was initially faced with a standard initial phone-screen with a manager from my department; they'll ask you about your interests in digital marketing, your experiences and how that might relate to Kepler, and also about your strengths and weaknesses. That same day I was asked to schedule a second round (in-person) interview with senior analysts and a manager.
The next week I went into the office and met with senior analysts who were all really friendly and genuinely just trying to get to know you as a candidate. The interview was structured such that it was broken into 1) a behavioral-type interview and 2) a business case interview! Definitely should prep before hand and have detailed insight into which brands/campaigns you like and be able to analytically break down why it's so interesting/successful (e.g. market, competitors, customers, product mix, etc.). Then afterwards, I had an interview with a manager from my deapartment and looked at data sets and gave my recommendations based off of the information given-- it's all fairly straight forward, but I would urge you to carefully listen to the questions.
After a few days, I was asked to come into the office again for a final round interview, presenting on a presentation on a topic of my choice for 5 minutes and then speaking with an Associate Director. The presentation requires a lot of preparation and you should be well prepared to discuss in a compelling and analytical way.
After a few days I was told that the position was already filled, but that they had another opening for another department, so I begun preparing for that final round. I was really thankful they reached out to me instead of just dropping me, but I was also not eager for a fourth round. But the day of the scheduled interview, they reached out to me saying that there was availability for the position I originally applied for, called me, and gave me an offer.
Overall the interview process was very robust and helped me gain more comprehensive insight into the kinds of work I'd be doing at Kepler and had an overall great experience.