The classic Apple rainbow logo might reappear in future products, and might even show up as soon as this year (via MacRumors).
Apple Rainbow Logo
MacRumors cites “a well-connected MacRumors tipster, who in turn cites a corporate Apple employee in Cupertino.” Exactly which products the logo may appear on is unknown.
The Apple rainbow logo first appeared in 1977 on the Apple II, and was used until 1998, when Apple favored a white logo. However, the colors of the logo are still widely used in iOS and macOS found in certain UI elements.