PDCD1 and neoplasm: To explore TEX in LUSC, we carried out an expression profile analysis of multiple inhibitory receptors, such as CTLA4, PDCD1 (known as PD-1), LAG3, BTLA, TIGIT, HAVCR2 (known as TIM-3), IDO1, SIGLEC7, and VISTA. These inhibitory receptors were significantly upregulated in the tumour samples within the immune-stromal cluster (fold-change > 2, Benjamini-Hochberg false discovery rate [FDR] < 1.1 × 10−7) (Fig. 1G).