Google is testing faster Incognito searches in Chrome by preloading results, but this could come at the cost of your privacy.

Incognito modes generally do not prevent ... the Mozilla Foundation says your identity and activity remain fully exposed to search engines and third parties — think advertisers — regardless ...

To ensure total deletion of incognito search history, users should manually clear browser data, DNS caches, and temporary files on Android, iOS, Windows, and Mac devices using specific steps.