The tumour immune microenvironment is shaped by the crosstalk between cancer cells, immune cells, fibroblasts, endothelial cells and other stromal components. Although the immune tumour microenvironment (TME) serves as a source of therapeutic targets, it is also considered a friend or foe to tumour-directed therapies. This is readily illustrated by the importance of T cells in triple-negative breast cancer (TNBC), culminating in the advent of immune checkpoint therapy in combination with cytotoxic chemotherapy as standard of care for both early and advanced-stage TNBC, as well as recent promising signs of efficacy in a subset of hormone receptor-positive disease. In this Review, we discuss the various components of the immune TME in breast cancer and therapies that target or impact the immune TME, as well as the complexity of host physiology.

肿瘤免疫微环境是由癌细胞、免疫细胞、成纤维细胞、内皮细胞和其他基质成分之间的串扰形成的。尽管免疫肿瘤微环境（TME）是治疗靶点的来源，但它也被认为是肿瘤定向疗法的朋友或敌人。 T 细胞在三阴性乳腺癌 (TNBC) 中的重要性很容易说明这一点，最终导致免疫检查点疗法与细胞毒性化疗相结合的出现，作为早期和晚期 TNBC 的护理标准，以及最近的治疗对激素受体阳性疾病的一个子集的疗效有希望的迹象。在这篇综述中，我们讨论了乳腺癌中免疫 TME 的各个组成部分以及针对或影响免疫 TME 的疗法，以及宿主生理学的复杂性。