Although data dissecting the effects of these drugs on CD4+ T cells are still elusive, it was recently found that in melanoma patients treated with anti-PD-1/anti-CTLA4 the frequency of the T cell population characterized by a TFH-like phenotype (CD4+, Foxp3-, PD-1high) is modulated differently by the two drugs and is a negative prognostic factor of response to therapy (141). The gene discussed is PDCD1; the disease is melanoma.