Testing the Combination of APG-1252 (Pelcitoclax) and Cobimetinib in Recurrent Ovarian and Endometrial Cancers

Inclusion Criteria: * For dose escalation, patients must have histologically or cytologically confirmed recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer, or endometrial cancer that is metastatic or unresectable and for which standard curative or palliative measures do not exist or are no longer effective. For expansion, patients must have histologically or cytologically confirmed recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer * Prior lines: * Patients must have received at least one prior line of platinum-based systemic therapy. Platinum received together with radiation as a sensitizing agent is not considered a systemic line of therapy * Patients with low grade serous ovarian cancer must have received a prior MEK inhibitor at a demonstrated therapeutic dose (i.e., trametinib 1mg daily or higher; binimetinib 30mg twice daily or higher). Patients who have had prior cobimetinib must have been able to tolerate cobimetinib at the dose and schedule they would receive it on study * Patients with microsatellite instability (MSI) or mismatch repair deficient (dMMR) endometrial cancer must have received prior PD-1 or PD-L1 directed immunooncology (IO) therapy or be considered medically ineligible to receive such therapy * Patients with ovarian cancer must have platinum-resistant disease (progression within 6 months of last receipt of platinum) * Age \>= 18 years. Because no dosing or adverse event data are currently availab…