Threat modeling is a practice to proactively analyze the cyber security posture of a system or system of systems. Threat modeling can be conducted both in the design/development phases and for live system environments. An effective threat modeling enables the user to make risk-based decisions on what measures to implement proactively. It can be argued that threat modeling, when done well, can be the most effective way of managing and improving your cyber risk posture, as it can enable you to identify and quantify risks proactively and holistically and steer your security measures to where they create the best value.
Source: https://www.helpnetsecurity.com/2021/04/30/what-is-threat-modeling/