<p>The accurate control of immune responses in the tumor microenvironment is crucial for augmenting anti-cancer immunity. This work examined the function of STAT3 in modulating epigenetic and epitranscriptomic pathways during the differentiation of CD4 + T helper cells in non-small cell lung cancer (NSCLC). Employing CRISPR/Cas9 genome editing, STAT3 was specifically eliminated in CD4⁺T cells derived from NSCLC patients. Functional investigations demonstrated that the reduction of STAT3 markedly enhanced the production of T helper 1 (TH1) cytokines, notably IFN-γ, while concurrently diminishing immunosuppressive signaling. Epigenetic analysis revealed significant modifications in DNA and RNA methylation patterns, along with heightened R-loop formation—alterations linked to augmented transcriptional activity of anti-tumor immune genes. Moreover, STAT3-deficient CD4⁺T cells demonstrated an enhanced ability to activate cytotoxic T lymphocytes, facilitating the targeted eradication of tumor cells. All of these effects together made the NSCLC microenvironment’s immune system better at fighting cancer. Our results identify STAT3 as a crucial regulator of the genetic and epigenetic frameworks that influence T cell functionality in lung cancer. By combining RNA-guided genome editing with immune functional tests, we show that blocking STAT3 in a specific way could bring back strong anti-tumor immunity. This research underscores the therapeutic potential of STAT3-targeted therapies, presenting an innovative approach to alter T cell destiny and improve immune-mediated tumor eradication in non-small cell lung cancer (NSCLC). These methods could lead to the next generation of immunotherapies that improve clinical outcomes by fine-tuning both epigenetic and epitranscriptomic circuits.</p>