Genes with mRNA expression found to be significantly associated with OS and DFS (n = 14, [CCR6, CD1C, CD1E, CD40, EOMES, GBP2, HLAA, HLAB, HLAH, JAK3, NKAP, SIRPA, TLR5, XCL1]) were compiled to create a composite immune mRNA expression signature characteristically suppressed in CS‐ACC tumours compared to nonCS‐ACC (Table S2). This evidence concerns the gene XCL1 and adrenal cortex carcinoma.