Immune Checkpoint-Based Therapies in Colorectal Cancer—Current Approaches and Future Perspectives

Colorectal cancer (CRC) is the third most frequently diagnosed malignancy and the second leading cause of cancer-related mortality worldwide, underscoring the need for the development of more effective and durable therapeutic strategies. A key mechanism of tumor immune evasion involves activation of immune checkpoint pathways through the upregulation of inhibitory ligand expression within the tumor microenvironment, leading to lymphocyte exhaustion and impaired antitumor immunity. Consequently, immune checkpoints have emerged as important targets for immunotherapeutic intervention, with significant advances over the past decade. Nevertheless, despite demonstrated clinical benefits in selected patient subpopulations, the overall therapeutic efficacy of immune checkpoint inhibitors remains limited, particularly in the context of CRC. In this review, we provide a comprehensive overview of currently approved immune checkpoint-based immunotherapies for cancer treatment, with a specific focus on CRC, as well as ongoing clinical trials and evolving trends in this area. Furthermore, we discuss emerging targets and novel therapeutic strategies, with particular emphasis on innovative small-molecule inhibitors as potential alternatives to monoclonal antibody-based approaches. Finally, we outline future perspectives and potential directions for advancing immune checkpoint-targeted therapies in CRC.