I don't get it. Slack needs a productivity suite to fight off Microsoft eating their lunch with teams getting bundled for free with everything. Salesforce has no synergy with Slack that I can see. I guess you could deeply integrate with the CRM... but why would you want that abomination? The advantage of Slack is that it's centralized communication for the whole company. If it becomes bolted on to the CRM I guarantee other departments at companies will find a new tool.