CD4 and neoplasm: Strikingly, programmed death-1 ligand 1 (PD-L1) expression levels in tumor cells and programmed death-1 (PD-1) expression levels in tumor-infiltrating CD4+ and CD8+ T cells were increased after TFP treatment, implying that the combination of TFP with an anti-PD-L1 or anti-PD-1 antibody might have stronger synergistic anticancer effects.