This is an open-label, multi-center, Phase 1/2 study designed to evaluate the safety, tolerability, pharmacokinetics (PK), and efficacy of BLU-924, a pan-KRAS inhibitor, in participants with metastatic KRAS mutant pancreatic ductal adenocarcinoma (PDAC), non-small cell lung cancer (NSCLC), or colorectal cancer (CRC). The monotherapy part of the study includes Dose Escalation, Dose Enrichment, and Dose Expansion. Participants enrolled during Dose Escalation and Dose Enrichment will be evaluated for dose limiting toxicities (DLTs) to determine the MTD. Participants enrolled into disease-specific Enrichment cohorts will enable a more robust characterization of safety, PK, pharmacodynamics, and preliminary clinical activity. Enrolment into Dose Expansion will follow the identification of at least 1 recommended dose for expansion (RDFE) based on data from the Dose Escalation and Dose Enrichment. No combination arm is active at this time.