CTLA4 and head and neck squamous cell carcinoma: To further evaluate the availability of the constructed risk model in immunotherapy, we explored immune checkpoints of HNSCC (Kok, 2020) in different risk groups and discovered that the expression levels of PD-1(PDCD1), CTLA4, LAG3, TIGIT, and BTLA were all significantly upregulated in the low-risk group compared with the high-risk group according to TCGA-HNSCC and GSE65858 cohorts (all p < 0.01, Figures 7D–H, 8D–H).