Pattern recognition receptors is a core concept in immunology referring to germline-encoded molecules expressed by innate immune cells and other cell types that detect conserved molecular structures associated with pathogens (PAMPs) or cellular damage (DAMPs). Research in this area investigates the diverse families of these receptors, their specific ligands, downstream signaling pathways, and their critical role in initiating rapid innate immune responses essential for host defense and influencing adaptive immunity.