PDCD1 and non-small cell lung carcinoma: To understand the relationship of LAG-3 with PD-1, double LAG-3/PD-1 IHC staining was performed on non-small cell lung cancer (NSCLC), showing concomitant positivity across 92% of the 39 tissue samples analyzed, with 59% demonstrating co-expression on the same cell (Supplementary Figs. 1b,c and 2a).