CHK1i+LDHU triggered a variable level of PD-L1 expression in vitro in the melanoma cell lines used here, that appeared weaker than reported for a similar CHK1i combination in lung cancer models [25], although a stronger increase in plasma membrane staining of PD-L1 was observed in the YUMMUV melanomas that escaped immune control in vivo. This evidence concerns the gene CD274 and lung carcinoma.