The main goals of this study are to learn about the safety of sacituzumab tirumotecan with bevacizumab and if people tolerate it; and if people who take sacituzumab tirumotecan with or without bevacizumab live longer without the cancer getting worse than those who receive standard of care treatment.

This phase III trial compares the effect of bevacizumab in combination with carboplatin, paclitaxel and pembrolizumab to the usual treatments of carboplatin and paclitaxel with or without pembrolizumab in treating patients with stage III, IVA or IVB mismatch repair protein proficient (pMMR) and TP53 mutated endometrial cancer that may have spread from where it first started to nearby tissue, lymph nodes, or distant parts of the body (advanced) or that has come back after a period of improvement (recurrent). Bevacizumab is in a class of medications called antiangiogenic agents. It works by stopping the formation of blood vessels that bring oxygen and nutrients to tumor. This may slow the growth and spread of tumor. Carboplatin is in a class of medications known as platinum-containing compounds. Carboplatin works by killing, stopping or slowing the growth of tumor cells. Paclitaxel is in a class of medications called antimicrotubule agents. It stops tumor cells from growing and dividing and may kill them. Immunotherapy with monoclonal antibodies, such as pembrolizumab, may help the body's immune system attack the tumor, and may interfere with the ability of tumor cells to grow and spread. Adding bevacizumab to the combination of carboplatin, paclitaxel and pembrolizumab may be more effective than the usual treatment combinations of carboplatin and paclitaxel with or without pembrolizumab in treating patients with advanced or recurrent pMMR and TP53 mutated endometrial cancer.