Background <p>Lung adenocarcinoma (LUAD), a common lung cancer subtype, is significantly influenced by the immune microenvironment. Immune checkpoint inhibitors have shown limited efficacy in Lung adenocarcinoma due to the immunosuppressive tumor microenvironment (TME). Identifying predictive biomarkers for immunotherapy response remains an urgent clinical need.</p> Methods <p>Multi-Omics data of LUAD were analyzed to investigate the immune microenvironment in LUAD. Single cell RNA-seq was used for exploring the intercellular communication mechanisms in TME. Spatial transcriptomic analysis confirmed the spatial co-localization of SPP1⁺ Malignant and CXCR4⁺ TAM, while in vitro experiments validated the functions of biomarker.</p> Results <p>This study delineated the cellular heterogeneity and dynamic shifts within the LUAD tumor microenvironment, resolving the malignant transformation trajectory. Crucially, we identified SPP1⁺ malignant and CXCR4⁺ TAM crosstalk as a driver of exhaustion of CD8T, which induced poor immunotherapy response. Moreover, this study indicated that the immune escape potential of patients in high infiltration of SPP1⁺ malignant and CXCR4⁺ TAM increased, and the efficacy of immune checkpoint suppressive therapy might be poorer. Spatial transcriptomics confirmed co-localization of SPP1⁺ Malignant and CXCR4⁺ TAM, while in vitro experiments demonstrated that CXCR4 plays an important role in the functions of LUAD cells.</p> Conclusions <p>This study uncovers the SPP1⁺ malignant and CXCR4⁺ TAM crosstalk as a novel TME-driven resistance mechanism and provides a potential biomarker for stratifying LUAD patients likely to benefit from immunotherapy.</p>