Recently, the RNAscope assay, which employs in situ hybridization of FFPE tumour samples [23–25], might be a promising method for assessing PD-L1 mRNA levels in various types of solid tumours [25–27] to provide for the PD-L1 expression level independent of IHC assays in melanoma [27]; however, this method has rarely been described in CHL. Here, CD274 is linked to melanoma.