Toll-like receptors (TLRs) are crucial for the innate immune response in vertebrates, enabling phagocytes like neutrophils, macrophages, and dendritic cells to distinguish between pathogens and self. TLRs recognize conserved microbial motifs, triggering immediate defensive responses such as antimicrobial peptides and cytokines. TLR signaling involves multiple pathways, with MyD88 and TRAF6 playing key roles. MyD88 is essential for most TLR signaling, except TLR3, which uses a different pathway. TLR3 signaling is independent of MyD88 and involves TRIF, which is crucial for TLR3 and MyD88-independent TLR4 signaling. Other adaptors like TIRAP and TRIF are involved in different signaling pathways, contributing to the specificity of TLR responses. The signaling pathways differ between TLRs, with some using MyD88-dependent and others MyD88-independent pathways. Understanding these pathways is vital for developing therapies against infectious diseases, septic shock, cancer, and autoimmune diseases.Toll-like receptors (TLRs) are crucial for the innate immune response in vertebrates, enabling phagocytes like neutrophils, macrophages, and dendritic cells to distinguish between pathogens and self. TLRs recognize conserved microbial motifs, triggering immediate defensive responses such as antimicrobial peptides and cytokines. TLR signaling involves multiple pathways, with MyD88 and TRAF6 playing key roles. MyD88 is essential for most TLR signaling, except TLR3, which uses a different pathway. TLR3 signaling is independent of MyD88 and involves TRIF, which is crucial for TLR3 and MyD88-independent TLR4 signaling. Other adaptors like TIRAP and TRIF are involved in different signaling pathways, contributing to the specificity of TLR responses. The signaling pathways differ between TLRs, with some using MyD88-dependent and others MyD88-independent pathways. Understanding these pathways is vital for developing therapies against infectious diseases, septic shock, cancer, and autoimmune diseases.