It is of great clinical significance to discover novel biomarkers for neck squamous cell carcinoma (HNSCC) treatments. We discovered a potential cancer-related gene, Cornichon Family AMPA Receptor Auxiliary Protein 4 (CNIH4), that can be a biomarker for HNSCC.We access multiple open databases and analyzed bulk mRNA-sequencing, protein staining, and single-cell mRNA-sequencing data of HNSCC and investigated the diagnostic and prognostic value of CNIH4 in HNSCC. The potential association between CNIH4 and the immune microenvironment of HNSCC was also estimated.CNIH4 was significantly up-regulated in HNSCC compared with non-cancer tissues. Higher CNIH4 resulted in a shorter overall survival time and we further constructed a survival nomogram for clinical applications. 2012 and 421 genes were identified as positive and negative differentially expressed genes of CNIH4 in HNSCC respectively. These genes were mostly mapped to "Cell cycle", "DNA replicate", "Cytokine-cytokine receptor interaction" KEGG pathways. Functions associated with CNIH4 were "stemness", "cell cycle", and "DNA repair" in single-cell data. CNIH4 potentially affected immune cell infiltration levels and cancer immune therapy.CNIH4 is a potential diagnostic and prognostic biomarker associated with cancer stemness and immunity in HNSCC.