In addition, the nectin-2 overexpressed on cancer cells or antigen-presenting cells suppresses immune cell activation, as an immune checkpoint, by binding to the nectin-2 receptor (poliovirus receptor-related immunoglobulin domain-containing, PVRIG) that is expressed on the surface of cytotoxic T (CD8+ T cells) and natural killer (NK) cells. Here, PVRIG is linked to cancer.