Tempus AI agreed to buy Personalis for $1.5 billion, aiming to deepen its position in molecular residual disease testing. Personalis’ tumor-informed MRD approach complements Tempus’ tumor-naive offerings, and the companies expect the deal to close in late 2026 or early 2027, subject to regulatory and shareholder approvals. The acquisition follows Personalis’ growing payer coverage and Tempus’ existing commercial partnership.