A Study of LY3484356 in Chinese Participants With Advanced Breast Cancer

Inclusion Criteria: * Native Chinese participants must be of an acceptable age to provide informed consent * Have locally advanced (not amenable to curative treatment by surgery) or metastatic disease and be an appropriate candidate for experimental therapy in the judgment of the investigator, after available standard therapies have ceased to provide clinical benefit * Have a diagnosis of ER+, HER2- breast cancer * Female participants have postmenopausal status due either surgical/natural menopause or ovarian suppression * If postmenopausal status is due to ovarian suppression, participants must have a negative serum pregnancy test and agree to use highly effective, medically approved precautions to prevent pregnancy * Have a performance status less than or equal to (≤)1 on the Eastern Cooperative Oncology Group (ECOG) scale * Have adequate organ function * Must be able to swallow capsules/tablets Exclusion Criteria: * Have symptomatic central nervous system (CNS) metastasis and/or carcinomatous meningitis * Have a serious concomitant systemic disorder * Human immunodeficiency virus (HIV) positive patients are excluded unless they are well controlled on highly active antiretroviral therapy with no evidence of autoimmune deficiency syndrome-defining opportunistic infections within the last 2 years, and cluster of differentiation 4 (CD4) count greater than (\>)350 cells/microliter (μL) * Active hepatitis B or C virus infection * Severe renal impairment, interstitial l…