I have used Integration of Slack with both Confluence and Jira,
Confluence really helps to maintain a Doc for a Jira Ticker ( linkable both the ways).
Slack integration helps to get notification on any changes on Jira Ticket or Confluence page, which had help to check and Priortize
I love the Slack integration that tells you when a new Jira issue has been created... since I spend all day in Slack it's nice to be able to track it there!