CTLA4 and neoplasm: Besides, the PD-1 and CTLA-4 immune checkpoints, lymphocyte activation gene 3 protein (LAG3), and T-cell immunoglobulin mucin-3 (TIM3) are expressed in some types of NK cells, with their ligands potentially taking part in dampening NK anti-tumor responses; as a result, blockade of interaction with checkpoint inhibitors boosts the activity of NK cells.743–745