The incident management platform VictorOps handles the distribution of messages from dozens of different sources, which can be selected as integrations directly in the web interface. A generic REST backend is available for Checkmk.
You do not need to explicitly activate the notifications from Checkmk, only the REST endpoint address:
In VictorOps under Integrations, call the REST Generic item.
Copy the displayed REST endpoint URL.
In Checkmk you only need to specify this key:
For the Notification Method select the item VictorOps.
Enter (insert) the copied URL under VictorOPS REST Endpoint.
For testing you can use the Fake check results and Custom notification commands.