RecruitingPhase 2Drug trialRESOLVE: Abemaciclib + Letrozole +/- Metformin or Gedatolisib in Endometrial CancerThis research study is studying a combination of targeted therapies as a possible treatment for estrogen-receptor positive (ER+) endometrial cancer. The drugs involved in this study are: * Abemaciclib (also known as Verzenio™) * Letrozole (also known as Femara®) * Metformin (also known as Glucophage®) * Gedatolisib (also known as PF-05212384)