Finally, considering that some biomarkers, such as MSI (Microsatellite instability), TMB (Tumor mutational burden), and PD-L1, have already been successfully used to predict and monitor PD-1 blockade therapy, it would be reasonable to evaluate these biomarkers or pursue other novel OV-specific biomarkers to better control and improve the OV-combined immunotherapy (144–147). Here, PDCD1 is linked to neoplasm.