Exploratory biomarker analyses from the JAVELIN Bladder 100 trial found that in the avelumab + BSC arm, OS benefit was positively associated with PD‐L1 expression by tumor cells, tumor mutational burden (TMB), CD8+ T cells, APOBEC mutation signatures, expression of genes underlying innate and adaptive immune activity, and the number of alleles encoding high‐affinity variants of activating Fc gamma receptors, highlighting that complex biologic pathways underlie treatment outcomes.16 This evidence concerns the gene CD274 and neoplasm.