Abstract: The Nobel Prize in Physiology and Medicine of 2018 were awarded to James P. Allison and Tasuku Honjo for their discovery of cancer therapy by inhibition of negative immune regulation. James P. Allison discovered CTLA-4 can function as a brake on the immune system, while Tasuku Honjo discovered PD-1 can also operate as a brake on the immune system with a different mechanism. Nowadays, cancer immunotherapy based on PD-1/PD-L1 inhibitors has made great progression. This review will go through the discovery of PD-1/PD-L1 and CTLA-4 and their molecular mechanism as well as the available inhibitors for PD-1 and PD-L1. It will emphasize the significance of immune therapy in cancer treatment.

Key words: 2018 Nobel Prize in Physiology and Medicine, cancer immune therapy, PD-1/PD-L1, CTLA-4