The IBM interview process is ultimately extremely long and tiring. You often find yourself waiting weeks to months between steps with little to no updates whatsoever. This extends from the beginning to the end of the interview process, it took several weeks to hear anything back after even the final onsite interview.
The interviews themselves range from online cognitive exams to typical coding exams and online behavioral interviews, ending with an onsite "Finish Line" interview. The interviews themselves were fair and pleasant, but I cannot recommend applying to IBM for anyone looking for immediate work.