γδ T cells recognize tumor antigens in a major histocompatibility complex-independent manner and can be used as a useful tool for detecting antitumor activity in vitro.6,31 We hypothesized that the combination of butyrate and anti-PD-1 might be involved in promoting antitumor immunity in γδ T cells in vitro. The gene discussed is PDCD1; the disease is neoplasm.