The primary function of an engine in Cortex XSOAR is to execute playbooks, scripts, commands, and integrations. This allows the platform to automate and orchestrate security operations tasks, helping security teams respond to incidents more efficiently.

Reference: https://www.paloaltonetworks.com/blog/security-operations/playbook-of-the-week-phishing-for- trouble-with-cortex-xsoar/

The primary purpose of Cortex XSIAM's machine learning-led design is to automate the handling of the bulk of incidents. By leveraging machine learning, it can automatically classify, group, and respond to incidents, reducing the need for manual intervention and increasing efficiency in incident management.