Architectural threat modeling is the practice of systematically identifying potential threats against a system before those threats materialize. Common frameworks include STRIDE (Spoofing, Tampering, Repudiation, Information Disclosure, Denial of Service, Elevation of Privilege) and PASTA (Process for Attack Simulation and Threat Analysis).
Architects use threat models to prioritize which detection capabilities to build. A threat model for a financial institution will weight insider threats and fraud differently than one for a healthcare organization that focuses on ransomware and PHI exfiltration. The model drives the detection roadmap.