Our findings reveal three key aspects of MZB1’s involvement in ovarian carcinogenesis: (1) its tumor-suppressive functions through direct modulation of cancer cell proliferation/migration, (2) its critical immunomodulatory role within the TIME, and (3) its unique expression patterns in chemoresistant histological subtypes, particularly ovarian clear cell carcinoma (OCCC). Here, MZB1 is linked to ovarian clear cell cancer.