The TCR delta chain is a crucial component of the γδ T cell receptor (TCR), forming a heterodimer with the TCR gamma chain. This TCRγδ complex is primarily expressed on the surface of γδ T cells and is capable of recognizing a diverse range of antigens, including non-peptide small molecules and glycolipids. Unlike αβ T cells, the TCR delta chain generates diversity through V(D)J recombination, but it has a relatively small gene repertoire and lacks the capacity for somatic hypermutation. The TCRγδ complex associates with the CD3 complex to form an octameric structure, which is involved in T cell activation and signaling. γδ T cells possess both adaptive and innate immune characteristics, allowing them to rapidly respond to pathogen infections, tumor growth, and tissue damage.