Please see https://jira.atlassian.com/browse/JSWSERVER-16300 and https://jira.atlassian.com/browse/JSWSERVER-4669 

We are after this functionality in Kanban/Scrum boards for Jira Cloud.  We use initiatives to group related Epics together.

We note we can see the initiative-epic relationship in advanced roadmaps, however use a Kanban/Scrum board to display epics needing high-level requirements and elaboration.  As we have more than a few initiatives, the current process of creating a query each time is tedious.

As a workaround, you can add swimlanes queries for each initiative you want to.