Together, these results reveal that HRD tumors exhibit diverse and context-dependent immune microenvironments, ranging from inflamed, immune-responsive niches (characterized by CD8+ TILs, mDCs, and M1 macrophages in dHpC cancers) to immune-excluded or inert phenotypes (dominated by CAFs, neutrophils, and naïve lymphoid cells) in dCpH and stromal-rich cancers. This evidence concerns the gene CD8A and hypoparathyroidism-retardation-dysmorphism syndrome.