Until now, you have been learning to fly in a single crew environment. The Multi-Crew Cooperation (MCC) course takes the skills you have learnt and adapts them to work in a multi-crew environment. You also start to learn generic procedures, which are used in airline operations.
The Jet Orientation Course (JOC) is designed to bridge the gap between gaining you fATPL and commencing your first type rating. The course is aimed at gaining further knowledge and developing skills of commercial aircraft handling.
Although the MCC & JOC are stand alone courses, you will often find the training providers combine them into a joint course.