I interviewed at Columbia Coordinated Biomed program G&D track, so my experience may be not directly relevant. The first day was student only events, where ppl could just get to know each other and ask some tips from current students since they know basically all the interviewers. Next day is the program overview and the actual interviews. Basically the same set up like other programs but they set every applicant up with 5 faculty members in one day; so everyone was talking to someone during the time slots; be prepared for kinda grilling questions as I have heard from the others. I personally didn't get that many technical questions but they were also very interested in knowing what was my role in the research experience. And if you are paired up with professors who are not in ur area, prepare to ask them more questions about their research/the particular program to fill the time since the conversation probably won't go into ur experience into the degree you want.
One funny thing about this interview was that the faculty interviewers held a meeting immediately after all the interviews and it went over time, so we the interviewees just hang out on Zoom waiting for the faculty social events and speculating what was going on in that meeting.
Anyway best of luck!