In addition, butyrate triggers CD8+ T cells activity to enhance efficacy of PD-1 antibody.59 We further find that the capacity of butyrate blocking tumor growth under psychological stress in immune-deficiency mice is less than the effect in immune-competent mice (data not shown), suggesting butyrate might regulate anti-tumor immunity in mediating stress-induced cancer progression. Here, CD8A is linked to Immunodeficiency.