Hide message screens from screenshots, in Settings: Blocks screenshots and the recent-apps preview on conversations, quarantine and “Why?”.
Why: some scams ask people to share their screen or install an app that records it. With this on, such apps see a blank screen on your messages, and the recent-apps view doesn't show their content.
The downside: you can't take screenshots of messages yourself while it's on. To report a scam, use Report or Share evidence… instead of a screenshot, or turn the setting off for a moment.