The immune system has the potential to kill cancer. When the body’s normal cells mutate and develop malignant growth, the immune system will immediately activate the intrinsic immune system and adaptive immune response so as to quickly remove the mutated cells, thus preventing the occurrence of cancer and maintaining the stability of self. However, the development of cancer is a complex process, and the immune factor of cancer development is often due to the defect or absence of the strong immune surveillance function that exists in the normal state of the body, which leads to the early development of tumor and the failure to choke out the tumor cells in time, resulting in the continued development of tumor cells. There are many PD-1 and PD-L1 immune drugs that can help tumor patients to clear the tumor cells that have already occurred and inhibit tumor metastasis and accelerate tumor regression.