CD4 and melanoma: In this context, both CD8+ and CD4+ T-cells represent the prevalent immune infiltrating populations found nearby melanoma cells but recent studies revealed that the presence of other molecules may potentially correlate with prognosis as the loss of expression of p16, the switch of the M2/M1 polarization of macrophages and the levels of immune checkpoints including PD-1 and VISTA (V-domain Ig suppressor of T-cell activation) (7–9).