It is one of the features recently released by Microsoft Power BI Team.
Actually it a very simple feature but more effective. You can check the spotlight for any visuals or elements that you added in your report.
You can see this option when you click “…” (Three dots) on any visual’s top right side.
It enables you to highlight only the specific report element from your report. During the presentation, if you want to highlight any visuals or elements then spotlight can be used.
It also can be added as a separate bookmark. Refer bookmark feature in Power BI.