One of the mechanisms used by melanoma for avoiding the CD8+ T cell antitumor action is the downregulation of MHC I. This reduction should support the removal of melanoma cells due to the capability of NKs to recognize and specifically eliminate cells expressing low levels of MHC I. Therefore, NKs appear a good target population for melanoma immune therapy [115,116,117]. The gene discussed is CD8A; the disease is melanoma.