A Study of LY4170156 in Participants With Selected Advanced Solid Tumors

The purpose of this study is to find out whether the study drug, LY4170156, is safe, tolerable and effective in participants with advanced solid tumors. The study is conducted in two parts - phase Ia (dose-escalation, dose-optimization) and phase Ib (dose-expansion). The study will last up to approximately 4 years.

Inclusion Criteria: * Have one of the following solid tumor cancers: * Dose Escalation: Ovarian (epithelial ovarian, primary peritoneal, and fallopian tube) cancer, endometrial cancer, cervical cancer, non-small cell lung cancer (NSCLC), triple negative breast cancer (TNBC), pancreatic cancer, or colorectal cancer (CRC) * Dose Optimization: Ovarian (epithelial ovarian, primary peritoneal, and fallopian tube) and endometrial cancer * Dose Expansion: Low grade serous ovarian cancer, cervical cancer, NSCLC, and TNBC Exclusion Criteria: * Individual with known or suspected uncontrolled central nervous system (CNS) metastases * Individual with history of carcinomatous meningitis * Individual with active uncontrolled systemic bacterial, viral, fungal, or parasitic infection * Individual with evidence of corneal keratopathy or history of corneal transplant * Any serious unresolved toxicities from prior therapy * Significant cardiovascular disease * Prolongation of QT interval corrected for heart rate using Fridericia's formula (QTcF) ≥ 470 milliseconds (ms) * History of pneumonitis/interstitial lung disease * Individuals who are pregnant, breastfeeding or plan to breastfeed during study or within 30 days of last dose of study intervention