Lung cancer is the leading cause of cancer related deaths in the United States. Given that the lung is a barrier mucosal organ, the lung provides a unique immunoregulatory environment. Therefore, we hypothesized that lung cancer immunoregulation differs from that of other malignancies, and understanding these unique pathways can assist in designing lung cancer specific therapeutics. Today, immunotherapies accentuate the CD8+ T cell immune response, including the production of the proinflammatory cytokine IFN-γ. However, in comparison with melanoma patients, lung cancer patients tend to have decreased responsiveness to these therapies. We aimed to understand this differential response through evaluating the role of CD8+ T cells and IFN-γ in the lung tumor microenvironment. Specifically, we noted a noncanonical role of both CD8+ T cells and IFN-γ in promoting rather than ameliorating the growth of lung adenocarcinomas in a variety of lung tumor models. In addition, we identified lung cancer cells themselves as prominent producers of IFN-γ in the tumor microenvironment, and this IFN-γ functions both directly and indirectly to promote lung tumor survival and growth. Directly, IFN-γ signaling within the lung tumor cells enhances proliferation of lung tumor cells and further increases IFN-γ production by these cells. Indirectly, IFN-γ secreted by the lung tumor cells induces alterations in the chemokine production of CD8+ T cells, specifically enrichment of CCR5 chemokines: CCL3 and CCL4. In turn, these chemokines attract CD4+Foxp3+ T regulatory cells (Tregs) into the tumor bed generating an immunosuppressive environment advancing tumor progression. Neutralization of IFN-γ, depletion of CD8+ T cells, or blockade of CCR5 on Tregs resulted in reduced lung tumor growth identifying this IFN-γ/CD8/CCR5 axis as a unique immunoregulatory mechanism operating in lung adenocarcinoma. Based on human samples, this immunoregulatory pathway may operate in approximately 50% of lung adenocarcinomas, thus providing a unique framework for devising novel, targeted immunomodulating strategies in the context of lung cancer.