Some resistance mechanisms are known and are driven by the biology of the melanoma, including downregulation of MHC molecules, loss of antigen expression, negative feedback causing PD-L1 upregulation in response to INF-γ production by T-cells and reduction in chemokine expression including CCL3, CSCL1, CXCL2 and CCL4 [151]. Here, CD274 is linked to melanoma.