Tumor Immune Microenvironment and Current Status of Immune Checkpoint Inhibitor Therapy in Colorectal Cancer Liver Metastasis

Colorectal cancer is one of the most common malignancies worldwide, with liver metastasis being one of its primary metastatic patterns and a significant cause of death. For most patients with unresectable colorectal cancer liver metastasis, a comprehensive treatment strategy that includes chemotherapy and targeted therapy is the primary therapeutic strategy. However, significant breakthroughs in immune therapy for liver metastasis have yet to be achieved. In this article, we summarize the characteristics of the immune microenvironment in colorectal cancer liver metastases and the mechanisms of immune resistance. Additionally, we compile recent clinical trial results on immune combination strategies and biomarker studies and discuss the prospects for applying immune checkpoint inhibitors in the treatment of colorectal cancer liver metastasis.