Peritoumorally administered IFNβ increases PD-1 expression on TILs, boosts anti-PD-1 Ab’s anti-tumour immune response, and reduces mRNA expression and Th2-related chemokine production, thereby suppressing Treg recruitment. While the combination treatment with anti-PD-1 Ab increased the therapeutic impact of IFNβ. The gene discussed is PDCD1; the disease is neoplasm.