PDCD1 and neoplasm: Given that evidence of significant and durable anti-tumor efficacy has been demonstrated using PD-1/PD-L1 inhibitors in several NSCLC clinical trials [5–9], numerous efforts are ongoing to identify determinants of response, including PD-L1 expression [5–9, 22, 23], CD8+ TIL [24], smoking status [7–9] and mutation/neoantigen burden [25].