CMTM6 and melanoma: Furthermore, they demonstrated that downregulation of CMTM6 resulted in a reduction in PD-L1 expression in cancer cells, dendritic cells, and xenografts derived from patients with melanoma, with no influence on PD-L1 transcription levels and rather that CMTM6 is present at the cell surface where it associates with the PD-L1 protein and reduces ubiquitination of PD-L1, leading to the prolongation of PD-L1 protein half-life [25].