Went thru 4 rounds of interviews, with multiple individuals each round. Some questions were more behavior question getting to know you the person, while a majority of them were technical and "How would you approach this situation" questions. This was other than the phone screens that were done.

I was interviewed by a panel of five employees from different levels/positions who took turns asking me questions. The interviewer panel included my prospective supervisor, an HR employee, a PhD-level scientist, and two laboratory technicians. It lasted a little over one hour and it was an overall enjoyable experience. I prepared answers ahead of time using the STAR method, but I did struggle at times to answer questions when they asked to provide examples. Prepare an abundance of examples and scenarios ahead of time, read up on Merck's DEI goals, and be knowledgeable of their history and aims. Be prepared to ask the interviewers questions. The interview probably could have been included before the 75-minute mark, but they graciously answered my questions and continued to ask for more details about my experience etc.