Ovarian cancer participants will be asked to have two tumor biopsies during the research study. The first biopsy will be done prior to receiving the participants' assigned treatments as a part of their cancer care and the second biopsy will be done about 3-7 days after starting treatment. Participants who will undergo neoadjuvant treatment and then surgery, will also have their tumor tissue collected during surgery. Participants whose disease worsens while on treatment will also be asked to have an additional, optional tumor biopsy.