This was a pretty standard academic interview. My experience was a bit peculiar, since I was continuing along in the lab where I did my PHD, but typically, the process goes something like this: Duke will fly a candidate in the night before before handing the candidate off to the lab recruiting them. The candidate will then spend 1 day meeting and interviewing with the individual members of the lab. At some point, the candidate will be asked to give a 1 hour seminar to the prospective lab (smallest case) or the department in which the lab belongs. Afterwards, lab members/the PI will usually take a day or two to decide on whether to give the candidate an offer.

Pretty casual and straightforward. Welcoming faculties and staffs. The interview is more like a confirmation once the decision is made by the hiring personnel. Just providing a data point here.