The risk of all-grade diarrhea after PD-1/PD-L1 inhibitor monotherapy in Carcinoma of the Head and Neck and Gastric cancer patients were significantly decreased (RR 0.50, 95%CI: 0.26-0.98, P=0.043; RR 0.23, 95%CI: 0.12-0.42, P=0.000 Figure 2B). Here, PDCD1 is linked to carcinoma.