CD47 (also known as Rh-associated protein, GP42, integrin-associated protein (IAP), and neurophilin,) is an immunoglobulin-like protein that interacts with its receptor, Signal-regulatory protein alpha (SIRPα), on macrophages. This binding interaction regulates transmigration, oxidative burst cytokine production, and phagocytosis, creating a “don’t eat me” signal. CD47 is ubiquitously expressed on the surface of normal cells, but is overexpressed in numerous cancer cells, where it is thought to contribute to the resistance of tumors to phagocyte-dependent clearance. The binding of Programmed Cell Death Protein 1 (PD-1), a receptor expressed on activated T-cells, to its ligands, PD-L1 and PD-L2, negatively regulates immune responses. PD-1 ligands are found on most cancers, and the PD-1:PD-L1/2 interaction inhibits T-cell activity and enables cancer cells to escape immune surveillance. The PD-1:PD-L1/2 pathway is also involved in regulating autoimmune responses, making these proteins promising therapeutic targets for a number of cancers, as well as multiple sclerosis, arthritis, lupus, and type I diabetes