As shown in Figures 3A–F, we found that the PD-L2, PD-1, LAG3, TIGIT, CTLA4 expression levels in subtype C1 were higher than in C2, indicating that patients in subtype C1 with a high expression of immune checkpoint inhibitors were more likely to form an immunosuppressive microenvironment, further leading to tumor immune escape (Dunn et al., 2002). Here, PDCD1 is linked to neoplasm.