Cellular immunity mediated by T lymphocytes plays a central role in both initiate and adaptive immune responses. There are multiple subgroups of T lymphocytes, which are categorized into αβ T cells and γδ T cells distinguished by the expression of the featured αβ or γδ T cell receptor (TCR) on the cell surface. The common αβ T cells and special γδ T cells originate from a common progenitor in the thymus but are fundamentally different in surface markers, distributions, antigen recognition, and functions, both of which coordinate and cooperate to induce a diversity of immune responses against pathogens and antigens.