PDCD1 and non-small cell lung carcinoma: In non-small-cell lung cancer (NSCLC), early work showed that higher circulating CD4/CD8 ratios and lymphocyte percentages correlate with improved responses to anti-PD-(L)1 therapy, whereas elevated PD-1+ T-cell frequencies, neutrophil-to-lymphocyte ratio (NLR), and monocyte-to-lymphocyte ratio (MLR) predict poorer outcomes [71].