That is correct, you can control who sees what App by placing the App in one of the 3 streams available in Qlik Sense Cloud Business. Here is a short video that shows you how. Qlik Sense Cloud Business: working with users or groups - YouTube
Right now we do not have section access available in Qlik Sense Cloud Business. If you need that level of governance Qlik Sense Cloud Enterprise has that capability.
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Manager - Global Cloud Success Team at Qlik