CD274 and anemia (phenotype): The multivariate features selection procedure applied to data of 95 ICSM patients without missing values for the set of variables reported in Supplementary Table S1 (43 progression events within 6 months from the starting of the treatment, 70 progression events during the follow-up period) identified IHC PDL1, ECOG PS (binarized: 0–1 versus 2–3), anemia and NLR as the most informative subset of predictors of progression.