Dysfunction of anti-tumor immune responses is crucial for cancer progression. Immune checkpoint blockade (ICB), which can potentiate T cell responses, is an effective strategy for the normalization of host anti-tumor immunity. In recent years, immune checkpoints, expressed on both tumor cells and immune cells, have been identified
some of them have exhibited potential druggability and have been approved by the US Food and Drug Administration (FDA) for clinical treatment. However, limited responses and immune-related adverse events (irAEs) cannot be ignored. This review outlines the development and applications of ICBs, potential strategies for overcoming resistance, and future directions for ICB-based cancer immunotherapy.