Trigger a Sub-Playbook on Master Playbook Execution
A Playbook that has Playbook as an action node is called master Playbook. A Playbook that is added as an action node to a master Playbook is called nested or sub Playbook. If a Playbook has a Playbook node, then you can trigger the sub Playbook by executing the master Playbook.
For example, f a Playbook has a Playbook node and a node in a sub-Playbook performs an action such as Scan URL, then on executing the master Playbook, the sub-Playbook also get executed and node in a sub-Playbook scans the input URL.