PDCD1 and non-small cell lung carcinoma: PD-L1 is expressed in approximately 50% of NSCLCs (NSCLC), primarily in advanced squamous subtypes. Nivolumab binds to the PD-1 receptor and blocks its interaction with PD-L1 and PD-L2, thereby releasing the inhibition of immune responses mediated by the PD-1 pathway.