This is an open-label, multi-center Phase 1a/1b study designed to evaluate the safety, tolerability, preliminary antitumor activity, and PK of BBO-10203 as a single agent and in combination with Trastuzumab, Fulvestrant +/- Ribociclib, or FOLFOX + Bevacizumab in patients with locally advanced unresectable or metastatic (ie, advanced) solid tumors. The study includes a dose escalation phase and an expansion phase.