CD4 and neoplasm: It is plausible that the PD-1 blockade induced conversion of CD25+Foxp3+ CD4 Tregs into CD25−Foxp3+ CD4 Tregs38, since we observed the intratumoral transferred CD25+Tregs with PD-1 blockade had decreased tumor egress, along with increased conversion to IFNγ-producing CD25-Tregs.