PDCD1 and non-small cell lung carcinoma: In the clinical setting, the precedent for success with combination checkpoint therapy for NSCLC treatment is most salient, in which anti-CTLA-4 and anti-PD-1 combination therapy was approved by the FDA in 2016 as a first-line therapy and showed promising results of improved progression-free survival compared with anti-PD-1 therapy alone (13).