The Toll-like receptor (TLR) family is a part of pattern recognition receptors, including multiple members such as TLR1 to TLR10. They consist of an extracellular leucine-rich repeat (LRR) domain and an intracellular Toll/IL-1 receptor (TIR) domain, primarily located on the cell surface and endoplasmic reticulum of immune cells such as macrophages and dendritic cells. TLRs activate signaling pathways such as NF-κB and MAPK by recognizing pathogen-associated molecular patterns (PAMPs) and damage-associated molecular patterns (DAMPs), promoting inflammation and immune responses. The expression of TLRs is tissue-specific, and mutations or dysregulation are associated with various diseases, including infectious diseases, autoimmune diseases, and cancer.