Diarrhea in cancer patients can quickly lead to life-threatening consequences such as dehydration, electrolyte imbalance, shock, etc. Compared to chemotherapy-related diarrhea the immunological preparation of PD-1/PD-L1 is prone to cause autoimmune digestive diseases such as ulcerative colitis, and may also cause side effects of diarrhea. The gene discussed is CD274; the disease is cancer.