JAK1 and melanoma: Resistance to immunotherapy can also emerge, and melanoma cells resistant to PD-1 inhibitors show upregulation of receptors VISTA (V-domain Ig suppressor of T cell activation) and TIM-3 (T-cell immunoglobulin and mucin domain-containing 3), as well as acquisition of mutations in genes encoding JAK1 (Janus kinase 1), JAK2 (Janus kinase 2) and B2 M (beta-2-microglobulin), which results in reduced sensitivity to T-cell mediated killing [18, 19].