Tumours such as melanoma, non-small cell lung cancer (NSCLC), and head and neck squamous cell carcinoma (HNSCC), which are typically TMB-H due to exogenous exposure to UV light, tobacco, or alcohol-driven mutagenesis, often display robust CD8 + T-cell infiltration and proinflammatory immune microenvironments [175–177]. The gene discussed is CD8A; the disease is head and neck squamous cell carcinoma.