Pembrolizumab, a humanized monoclonal immunoglobulin IgG4 antibody targeting PD1 and blocking its interaction with PD-L1, was the first ICI to receive US FDA approval in 2016 for first-line treatment for advanced non-small cell lung cancer (NSCLC) in PD-L1 high EGFR/ALK wildtype NSCLC [14]. Here, PDCD1 is linked to non-small cell lung carcinoma.