This article focuses on the following predictive biomarkers related to anti-PD-1/PD-L1 immunotherapy (as shown in Table 1 and Figure 2): PD-L1, TMB, MSI-H/dMMR, tumor DNA-related biomarkers, peripheral blood-related biomarkers, intestinal flora-related biomarkers, TME-related biomarkers, T cell-related biomarkers, and immunohistochemistry (IHC) related biomarkers. The gene discussed is PDCD1; the disease is neoplasm.