You haven't provided enough information for people to provide focused recommendations. What is your role in the interview process? Are you technical and is th

You haven't provided enough information for people to provide focused recommendations. What is your role in the interview process? Are you technical and is the company depending on you to properly vet the candidate for technical skills? Then you need 90 minutes of concrete coding evaluation, etc. If you're just in the loop to make sure the candidate "fits" the culture, I suppose you could have a dialogue about anything... e.g. "soft" questions like "name a time a you and a coworker didn't get along and how did you handle it?" If it's a technical programming candidate, is it web front end work? CRUD LOB? back end engineering and scaling? custom algorithms work? The way you've posed your question is really wide open.