CD274 and melanoma: At least in part in response to interferon γ (IFN γ) released by CD8+ T cells (Taube et al, 2012), melanoma cells overexpress on their surface programmed death ligand 1 (PD-L1) and PD-L2, two prototypical immune checkpoint transmembrane ligands that interact with the PD-1 receptor present in CD8+ T cells (Kalaora et al, 2022).