A Study to Evaluate Safety/Tolerability of Immunotherapy Combinations in Participants With Triple-Negative Breast Cancer or Gynecologic Malignancies

In the dose escalation phase, the following will be assessed: * Arm A: escalating doses of etrumadenant in combination with PLD at standard doses will be assessed in participants with advanced metastatic triple-negative breast cancer or ovarian cancer. Eligible participants will receive oral administration of etrumadenant as well as intravenous (IV) infusion of PLD. The recommended dose (RDE) for expansion Arms 1 and 2 and escalation Arm C will be determined upon completion of this dose escalation arm. * Arm B: escalating doses of etrumadenant in combination with the NP at standard doses will also be assessed in participants with advanced metastatic TNBC. Eligible participants will receive oral administration of etrumadenant as well as NP infusion. The RDE of etrumadenant will be determined upon completion of this dose escalation arm. * Arm C: escalating doses of IPI-549 in combination with the RDE of etrumadenant (from Arm A) and PLD at standard doses will be assessed in participants with advanced metastatic TNBC or ovarian cancer. Eligible participants will receive oral administration of both etrumadenant and IPI-549 as well as IV infusion of PLD. The RDE of IPI-549 for expansion Arm 4 will be determined upon completion of this dose escalation arm. In the dose expansion phase, the following will be assessed: * Arms 1 and 2: Etrumadenant at the RDE in combination with PLD at standard doses may be assessed in participants with advanced metastatic TNBC or ovarian cancer. * Arm 3: Etrumadenant at the RDE in combination with NP at standard doses may be assessed in participants with advanced metastatic TNBC. * Arm 4: Etrumadenant and IPI-549 at the RDE in combination with PLD at standard doses may be assessed in participants with advanced metastatic TNBC. Overall duration of treatment will depend on how well the treatment is tolerated. Treatment may continue until unacceptable toxicity or progressive disease or other reasons specified in the protocol.