CD274 and neoplasm: ICPs are e.g., the programmed cell death protein 1 (PDCD-1, PD-1) expressed on T cells, its ligand CD274, the programmed cell death protein ligand 1 (PD-L1; B7H1) expressed on tumor cells and immune cells (T cells, B cells, DCs, NKs, macrophages), the cytotoxic T-lymphocyte-associated antigen (CTLA-4) expressed on T cells (T helper cells, cytotoxic T cells and regulatory T cells) and its immunological counterparts B7-1/B7-2 (CD80/CD86) expressed on antigen presenting cells (APCs: DCs, monocytes, macrophages and B lymphocytes).