Targeting cGAS-STING pathway is a promising strategy in tumor treatment. The pattern recognition receptor cGAS identifies dsDNA and catalyzes the formation of the second messenger 2'3'-cGAMP, activating the downstream interferons and pro-inflammatory cytokines through the adaptor protein STING. Notably, in tumor immune microenvironment, key components of cGAS-STING pathway are transferred among neighboring cells. The intercellular transmission under these contexts serves to sustain and amplify innate immune responses while facilitating the emergence of adaptive immunity. The membrane-based system, including extracellular vesicles transport, phagocytosis and membrane fusion transmit dsDNA, cGAMP and activated STING, enhancing the immune surveillance and inflammatory. The membrane proteins, including specific protein channel and intercellular gap junctions, transfer cGAMP and dsDNA, which are crucial to regulate immune responses. And the ligand-receptor interactions for interferons transmission amplifies the anti-tumor response. This review elaborates on the regulatory mechanisms of cell-to-cell communications of cGAS-STING pathway in tumor immune microenvironment. We further explore how these mechanisms modulate immunological processes and discuss potential interventions and immunotherapeutic strategies targeting these signaling cascades.