Thus, neither the expression pattern of PD-L1 on the tumor cell surface alone is sufficient to account for the mechanism of tumor immune escape nor accurate for predicting the response to anti-PD-1/PD-L1 treatment, although tumor tissue PD-L1 is the only indicator authorized by the FDA (Festino et al., 2016; Wang Q. et al., 2017; Li et al., 2019c; Martinez-Morilla et al., 2020). The gene discussed is PDCD1; the disease is neoplasm.