When I interviewed at GAMMA I got both business case interviews and technical case interviews. Business case interviews are as usual. Technical case interviews have the same structure with fit and Q&A, but includes a more technical case. E.g. our client is a grocery store chain who would like our help developing personalized promotions in their loyalty program. Typically you would then discuss defining the problem, what data you want and have, which models you would use, and how you would validate and test your model. I prepared by imagining problems like this for different companies, as well as by looking at past Kaggle competitions.