However, the effective response rate of PD-1 inhibitors in cancer patients, including lung cancer, is low, which is thought to be mainly affected by tumor mutational burden (Goodman et al. (2017), microsatellite instability (MSI), efficient DNA mismatch repair (DMMR) (Xiao and Freeman, 2015), and other factors. This evidence concerns the gene PDCD1 and neoplasm.