Recent advance of nanosized drug delivery systems targeting immune checkpoints for combination cancer immunotherapy

Immune checkpoint blockade (ICB) therapy has gained increasing attention due to its remarkable therapeutic performance. However, its therapeutic performance was highly impaired by the low immunogenicity of the tumors, insufficient intratumoral infiltration of the T lymphocytes, and the immunosuppressive tumor microenvironment. To address the challenge of current ICB therapy, nanosized drug delivery systems have been extensively exploited to deliver various immune modulators (e.g., chemotherapeutics, photosensitizers, and immune checkpoint inhibitors) for improved ICB therapy. In this review, we provide a brief overview of the recent advance of nanosized drug delivery systems for combination ICB immunotherapy. We also discuss the challenges and provide perspectives for the clinical translation of nanosized drug delivery systems for cancer immunotherapy.