PDCD1 and ovarian serous adenocarcinoma: High-grade serous ovarian cancers (HGSOCs) which are BRCA mutant/HRR deficient show increased CD8+ TILs, elevated levels of PD-1/PD-L1 expression and greater neoantigen load, indicating that certain OC subtypes may benefit from PD-1/PD-L1 blockade.