The cytokines strongly stimulate the expression of both PD-1 and PD-L1 (61), as well as maintain the expression of PD-1 on the surface of the anti-melanoma TEFF, initially sparked by the ligation of TCRs with cognate tumor Ags during the time when the TEFF cells were present in the TME before their relocation to the lung. Here, PDCD1 is linked to melanoma.