CD4 and neoplasm: Although PD-1 blockage has been reported to reinvigorate peripheral T cell clones that are dynamic exchanged with the tumor by a TCR Vβ complementarity-determining region 3 (CDR3) sequencing study [50], they did not really distinguish whether it was primarily CD4+ or CD8+ T clones that were relevant to the pathologic responses of PD-1 blockage.