We do not know whether the lack of HLA class I antigen and β2-m expression by tumor cells reflects an escape mechanism to nivolumab of BCC cells or whether nivolumab administration has facilitated the outgrowth of dormant tumor cells not expressing HLA class I antigen expression and subjected to the selective pressure of T cells unleashed by nivolumab. The gene discussed is MICA; the disease is skin basal cell carcinoma.