Background <p>CD8⁺ T cells play a key role in antitumor immunity, but their heterogeneity leads to inconsistent prognostic associations. CCR5 (C–C chemokine receptor type 5) is a key regulator of CD8⁺ T cell migration into the tumor microenvironment, suggesting that CCR5⁺CD8⁺ T cells may have unique antitumor functions and prognostic significance. However, this hypothesis has not yet been validated.</p> Methods <p>We investigated the role of CCR5⁺CD8⁺ T cells in tumors and their prognostic value in non-small cell lung cancer (NSCLC) through comprehensive analyses including bulk transcriptomic profiling of TCGA and GEO cohorts, single-cell RNA sequencing of 15 NSCLC patient samples, multiplex immunofluorescence staining of tumor tissues, and in vitro tumor cell co-culture killing experiments.</p> Results <p>We identified that high levels of CCR5⁺CD8⁺ T cell infiltration were significantly associated with improved overall survival across multiple cohorts and served as an independent prognostic factor. Gene enrichment analysis indicated that CCR5 upregulation is linked to T cell activation and enhanced antitumor immunity. CCR5 expression correlated more strongly with CD8⁺ T cell infiltration than that of other CCR family members. Functional assays revealed reduced tumor cell lysis following CCR5 antagonist treatment, indicating impaired T cell cytotoxicity. Single-cell analysis further showed that CCR5⁺CD8⁺ T cells represent a functionally potent antitumor subset.</p> Conclusion <p>CCR5⁺CD8⁺ T cells exhibit antitumor activity in NSCLC and could serve as a promising prognostic biomarker and therapeutic target.</p>