Immunotherapy, which shows great promise for treating patients with metastatic malignancies, has dramatically changed the therapeutic landscape of cancer, particularly subsequent to the discovery of immune checkpoint inhibitors. However, the responses to immunotherapy are heterogeneous and often transient. More problematic is that a high proportion of patients with cancer are resistant to such therapy. Much effort has been expended to identify reliable biomarkers that accurately predict clinical responses to immunotherapy. Unfortunately, such tools are lacking, and our knowledge of the mechanisms underlying its efficacy and safety is insufficient. The microbiota is increasingly recognized for its influence on human health and disease. Microbes create a pro- or an anti-inflammatory environment through complex interactions with host cells and cytokines. Emerging evidence indicates that microbes alter the efficacy and toxicity of immunotherapy by modulating the host’s local and systemic immune responses. It is therefore critically important to exploit the microbiota to develop biomarkers as well as to identify therapeutic targets that can be applied to cancer immunotherapy. This review provides insights into the challenges that must be addressed to achieve these goals.

免疫疗法在治疗转移性恶性肿瘤方面显示出广阔的前景，极大地改变了癌症的治疗方式，尤其是在发现免疫检查点抑制剂之后。但是，对免疫疗法的反应是异质的，通常是短暂的。更成问题的是，很大比例的癌症患者对这种疗法有抵抗力。为了确定可准确预测对免疫疗法的临床反应的可靠生物标记物，已经进行了很多努力。不幸的是，缺少这样的工具，并且我们对其功效和安全性背后的机理的了解不足。微生物群因其对人类健康和疾病的影响而日益得到认可。微生物通过与宿主细胞和细胞因子的复杂相互作用来创造促炎或抗炎环境。新兴证据表明，微生物可通过调节宿主的局部和全身免疫反应来改变免疫疗法的功效和毒性。因此，至关重要的是开发微生物群以开发生物标记以及鉴定可用于癌症免疫治疗的治疗靶标。这篇综述提供了对实现这些目标必须解决的挑战的见解。因此，至关重要的是开发微生物群以开发生物标志物以及鉴定可用于癌症免疫治疗的治疗靶标。这篇综述提供了对实现这些目标必须解决的挑战的见解。因此，至关重要的是开发微生物群以开发生物标记以及鉴定可用于癌症免疫治疗的治疗靶标。这篇综述提供了实现这些目标必须解决的挑战的见解。