2 rounds : Round 1 was talk about the ml models on my resume(went deep into their theory) and couple of case studies centered around amex's business model. Round 2 was case studies again and questions like why amex? both rounds were a mix of technical and hr.Would suggest strongly brushing up one's knowledge of credit cards and amex's revenue streams

They asked Case Studies on what parameters could be used for Machine Learning model, there were three rounds but in further rounds they asked theoretical Machine Learning based case studies.