What is the difference between an IPC CIS, CSE and a CIT certificate?

IPC-A-610 CIS (Certified IPC Specialist)
This CIS variant is intended for operators

IPC-A-610 CIT (Certified IPC Trainer)
This CIT variant is intended for anyone who wants to train operators to CIS themselves

IPC-A-610 CSE (Certified Standards Expert)
This CSE variant is intended for anyone who wants to become an expert in the field of the relevant standard. These experts are often used by companies as coordinators to correctly apply the standard within the company.