What is the main difference between SOAR and SIEM systems?

Security orchestration, automation, and response (SOAR) services are designed to integrate with a broader range of both internal and external applications. One of the main differences between SOAR and SIEM is that SOAR is automation, where as SIEM is not.
Both security information and event management (SIEM) and SOAR systems typically include threat and vulnerability management tools, as well as security operations’ automation capabilities.