BGB-53038

This is a first-in-human (FIH), open-label, multicenter, dose escalation and dose expansion study to evaluate the safety, tolerability, pharmacokinetics (PK), pharmacodynamics, and preliminary antitumor activity of BGB-53038 as monotherapy in participants with advanced or metastatic solid tumors harboring KRAS mutations or amplification, as well as when used in combination with tislelizumab (also known as BGB-A317) in participants with nonsquamous non-small cell lung cancer (NSCLC) and used in combination with cetuximab in participants with colorectal cancer (CRC). The study consists of 2 phases: Phase 1a Dose Escalation and Safety Expansion and Phase 1b Dose Expansion.