CD274 and melanoma: This contrasts with work showing that arginine deprivation with ADI‐PEG20 may enhance PD‐1/PD‐L1‐based immune checkpoint blockade via upregulation of PD‐L1 tumoural expression and modulation of a T‐cell infiltrate in aggressive tumour xenograft models including B16 melanoma (Brin et al., 2017).