NK cells play a role in various cancers, but their role in head and neck squamous cell carcinoma (HNSCC) still needs to be explored. All public data are obtained from the Cancer Genome Atlas Program (TCGA) database. All analysis was performed using specific packages in R software. In our study, we quantified the immune microenvironment of HNSCC through multiple algorithms. Next, we identified NK cell‐associated genes by quantifying NK cells, including SSNA1, TRIR, PAXX, DPP7, WDR34, EZR, PHLDA1 and ELOVL1. Then, we explored the single‐cell expression pattern of these genes in the HNSCC microenvironment. Univariate Cox regression analysis indicated that the EZR, PHLDA1 and ELOVL1 were related to the prognosis of HNSCC patients. Following this, we selected EZR for further analysis. Our results showed that the patients with high EZR expression might have a poor prognosis and worse clinical features. Biological enrichment analysis showed that EZR is associated with many oncogenic pathways and a higher tumour stemness index. Meanwhile, we found that EZR can remodel the immune microenvironment of HNSCC. Moreover, we noticed that EZR could affect the immunotherapy and specific drug sensitivity, making it an underlying clinical target. In summary, our results can improve the understanding of NK cell in HNSCC. Meanwhile, we identified EZR as the underlying clinical target of HNSCC.