在肿瘤微环境（TME）中，细胞释放的外泌体形成肿瘤细胞与免疫细胞之间的交互网络，从而调节TME中的免疫信号级联反应。作为细胞间通讯的关键信使，外泌体不仅负责将肿瘤细胞的抗原呈递给免疫细胞，还调节免疫细胞的活动，抑制免疫功能，尤其是促进免疫耐药性，这些因素都影响肿瘤的治疗效果。外泌体是一种小型囊泡，具有一些显著的优势，包括强大的生物活性、缺乏免疫原性和毒性以及强大的靶向性。基于这些特点，研究外泌体作为肿瘤治疗药物的生物标志物或载体已经成为相关领域的研究热点。本综述描述了外泌体在TME中细胞间通讯中的作用，总结了外泌体免疫治疗在克服肿瘤免疫耐药性方面的有效性，并系统地总结和讨论了来自不同细胞来源的外泌体的特点。此外，还讨论了外泌体相关治疗的前景和挑战。版权所有© 2023 Elsevier Ltd.保留所有权利。

In the tumor microenvironment (TME), exosomes secreted by cells form interactive networks between the tumor cells and immune cells, thereby regulating immune signaling cascades in the TME. As key messengers of cell-to-cell communication in the TME, exosomes not only take charge of tumor cell antigen presentation to the immune cells, but also regulate the activities of immune cells, inhibit immune function, and, especially, promote immune resistance, all of which affects the therapeutic outcomes of tumors. Exosomes, which are small-sized vesicles, possess some remarkable advantages, including strong biological activity, a lack of immunogenicity and toxicity, and a strong targeting ability. Based on these characteristics, research on exosomes as biomarkers or carriers of tumor therapeutic drugs has become a research hotspot in related fields. This review describes the role of exosomes in cell communications in the TME, summarizes the effectiveness of exosome-based immunotherapy in overcoming immune resistance in cancer treatment, and systematically summarizes and discusses the characteristics of exosomes from different cell sources. Furthermore, the prospects and challenges of exosome-related therapies are discussed.Copyright © 2023 Elsevier Ltd. All rights reserved.