PDCD1 and neoplasm: Our data also revealed that the genetic events that were associated with the micropapillary tumors may also contribute to the development of an innate immune escape for tumor cells with inactivated PD-1/PD-L1 signaling, so immunotherapy strategy of combination anti-PD-1/PD-L1 with anti-CTLA-4 drugs may benefit patient with micropapillary lung cancer.