Natural killer (NK) cells help regulate autoimmune reactions, but overactivation causes harm. A Tim-3 receptor is an immune checkpoint that prevents overactivation. Its malfunction is related to autoimmune diseases and is mediated by phosphorylation of Tim-3 and other ligands. Photophosphatidylserine (phoPS) is a photoswitchable instrument that regulates NK cells through Tim-3. PS is bound to multiple receptors; therefore it can be utilised against cancer, infectious disorders, and autoimmune diseases, though more in vitro and in vivo research studies are needed.