Checkpoint inhibitors, such as Pembrolizumab (anti-programmed cell death protein-1; PD-1) and Ipilimumab (anti-cytotoxic T-lymphocyte associated protein 4; CTLA4) bind to immune cells rather than directly to the tumour, and therefore may not require interactions with activating FcγRs. This evidence concerns the gene PDCD1 and neoplasm.