PDCD1 and neoplasm: Unprecedented efficacy was observed with the addition of standard chemotherapy to a PD-1 blockade with pembrolizumab, reducing the risk of death by half compared to chemotherapy alone in non-squamous NSCLC (OS at 12 months 69.2% vs. 49.4%) [4], and in squamous NSCLC regardless of tumor PD-L1 expression status (OS 15.9 vs. 11.3 months) [68].