PDCD1 and non-small cell lung carcinoma: Immunotherapy is a leading approach for treating advanced non-small cell lung cancer (NSCLC) by targeting the PD-1/PD-L1 checkpoint signaling pathway, particularly in tumors expressing high levels of PD-L1 (Jug et al. in J Am Soc Cytopathol 9:485–493, 2020; Perrotta et al. in Chest 158: 1230–1239, 2020).