HDAC1 and hypoparathyroidism-retardation-dysmorphism syndrome: Herein, for the first time, we conducted integrated scRNA‐seq and scTCR‐seq analyses of HRD and HRP HGSTOC tumors and found that HRD tumors were highly enriched in immunogenic epithelial cells, infiltrated FGFR1+PDGFRβ+ myCAFs, M1 macrophages, tumor reactive CD8+ T cells, and CD4+ Tregs, while HRP tumors were highly enriched in HDAC1‐expressing epithelial cells, indolent CAFs, M2 macrophages, and bystander CD4+/CD8+ T cells.