The application of nano-medicine to overcome the challenges related to immune checkpoint blockades in cancer immunotherapy: Recent advances and opportunities

Although immunosurveillance mechanisms are doing their best to counteract with the development of malignant cells, immune checkpoints may serve as the "Achilles' heel" that are exploited by malignant cells. Notably, a deep understanding of this fragile site of the immune system later led to the development of immune checkpoint blockades (ICBs). At the beginning of the discovery, it seemed that these agents could push the boundaries of cancer treatment, however, their life-threatening adverse events have muted the enthusiasm into their application in cancer. It was here that nanotechnology came to the aid of ICBs, as it became evident that the combination of nano-products with ICBs guarantees the delivery of the agents into the tumor nidus, where paralyzed immune cells are waiting for healing. In the present review, we tried to illustrate a new portrait from the befitting impacts of ICBs either as single or in a combined-modal strategy with nanoparticles.