I can't speak for all situations but this is how I was onboarded at Comerica:
I received a call a day or two after applying for a particular job with an interview scheduled a week out. At the interview I met with the person who would be my direct manager and the person that would train me, and to my surprise, was interviewed by a completely different manager and analyst. I wasn't sure if that was to throw me off or if they were genuinely interested in me but it worked out well. During the interview you'll be asked the questions you're probably expecting and have prepared for. Circumstantial questions, history, experience, etc. I would recommend being natural, they should already know your skills and experience with the information you provided on your resume or application so try to be yourself and human. Not to say you should be relaxed as if you're at home, but I get the sense they don't like "robots" here. Asking your interviewer questions and repeating what they said seems to help.