Hydroxychloroquine, Abemaciclib and Endocrine Therapy in Hormone Receptor Positive (HR+)/Her 2 Negative Breast Cancer

Part 1: 3+3 dose escalation of HCQ combined with abemaciclib in advanced solid tumors. Part 2: HCQ at top-dose level from part one is combined with abemaciclib and endocrine therapy in HR+/Her 2- advanced breast cancer (ABC) and divided into two cohorts based on prior exposure to endocrine therapy. Primary Objective 1. Dose-escalation cohort: To determine safety and tolerability of HCQ combined with abemaciclib. 2. Dose-expansion cohort: To determine safety and tolerability of HCQ combined with abemaciclib and endocrine therapy in HR+/Her2- ABC. Secondary Objectives 1. To assess the clinical efficacy of HCQ in combination with abemaciclib and hormone blockade in the dose- expansion cohort of advanced ER- positive breast cancer participants. 2. To assess the clinical efficacy of HCQ in combination with abemaciclib in the dose- escalation cohort