ICOS and hepatocellular carcinoma: Distinct HCC-enriched clusters shown in tSNE, CH1 (ICOS+CD69+TIGIT+) and CH5 (ICOS+CD69+CD103hi HLA-DR+PD-1hiTIGIT+Tim-3+) demonstrated that ICOS+ TRM cells could potentially be suppressed by multiple co-inhibitory checkpoint receptors in HCC (Figures 2B, D).