Exosomes: Key Messengers Mediating the Interaction Between Tumor Cells and CD8⁺ T Cells in the Tumor Microenvironment

In recent years, with an increasingly profound comprehension of the tumor microenvironment, it has been discovered that the constituent cells within the immune microenvironment, such as macrophages, CD4⁺T cells, and CD8⁺T cells, interact with tumor cells in manners conducive to tumorigenesis and progression. Exosomes play a pivotal role as essential mediators for intercellular material exchange and signal transmission in this context. Tumor cell-derived exosomes carrying cargo such as PD-L1 and ncRNAs engage with CD8⁺T cells to induce cytotoxic responses and facilitate immune evasion, thereby promoting tumor advancement. When combined with current immune checkpoint inhibitors like anti-PD-L1/PD-1 therapy, enhancing CD8⁺T cell function through exosomal pathways while monitoring and augmenting therapeutic effects can significantly improve efficacy. This review delineates the crucial role of exosomes derived from both tumor cells and CD8⁺T cells within the tumor microenvironment along with their impact mechanisms on both tumor cells and CD8⁺T cells. Furthermore, it summarizes the potential for clinical treatment in this realm when integrated with existing immunotherapy methods-particularly exploring the feasibility of clinical translation alongside engineering materials science techniques.