PDCD1 and hepatocellular carcinoma: Single‐cell transcriptomes of T cells from nonsmall‐cell lung carcinomas,29 hepatocellular carcinomas,30 colorectal carcinoma31 and breast carcinoma32 revealed that NKG2A (KLRC1), TIM‐3 (HAVCR2) and CD39 (ENTPD1) were expressed in the same unique CD8 T cell clusters and that PD‐1 (PDCD1), LAG‐3 (LAG3), TIGIT (TIGIT), NKG2D (klrk1), DNAM‐1 (CD226) and 2B4 (CD244) are far more globally distributed among multiple CD8 T cell clusters (Figure 6).