They're sort of connected but dont put that or they'll kill your marks, I've done an essay on this for biomedical sciences, do you want a basic or simple answer ? I'll throw you the basic one at the moment. Your lymphatic system is a 'system'
in your body that plays an important role in the
functioning of the immune system. It's basically a system of fluid, called lymph wouldn't you know it that carries protein molecules and other nutrients back to the blood there providing the
functions for your immune system (functions is a very important word in this topic). The purpose of those lymph vessels is to keep the fluid containing the nutrients constat around your cell, if you've got too much nutrients that they can't be absorbed through the capilary walls and such then they are converted into 'lymph' and transported
back to your blood by the lymphatic vessels.
Your immune system is simply a collection of organs and a circulatory system seperate from your
blood vessels containing highly specialised cells. The organs of your immune system are called the lymphoid organs. Extra marks - The word "lymph" in Greek means a pure, clear stream..... I think ??
In short, your lymphatic system aids the functioning of your immune system, and your immune system actually does the work.