2018 Nobel Prize for Medicine awarded to duo's work on cancer immunotherapy

James P. Allison and Tasuko Honjo discovered immune checkpoints that prevent T cells from attacking tumors. They identified proteins CTLA-4 and PD-1 on T cells that interact with tumor proteins, leading to the development of immune checkpoint inhibitors. These drugs block the pathways controlled by CTLA-4 and PD-1, allowing T cells to attack tumors. The FDA has approved these drugs for treating various advanced cancers, resulting in significant tumor regressions.

Explain the significance of the FDA's approval of immune checkpoint inhibitors.

List some types of cancers for which immune checkpoint inhibitors have been approved.