Apple is making separate macOS apps for Music, Podcasts, and TV. Those features are still in iTunes, although they have been split off in iOS. The apps would come in the next version of macOS, presumably called 10.15.
The Books app is already available for macOS, but is getting a new version, writes 9to5Mac. It is unknown whether these will be native apps or whether Apple will port the iOS apps to its desktop operating system via Marzipan. That happened in the latest macOS version, 10.14 Mojave, with a few apps, such as Stocks and Voice Memos. Developer Steve Throughton-Smith, who often finds unannounced cases in Apple code, said recently that he expects these to be UIKit apps that Apple ports from iOS to macOS via Marzipan.
Until now, the functions to listen to podcasts and music via Apple’s own streaming service were in iTunes, but that is probably possible in the new version with its own app. The TV app would be necessary, among other things, due to the arrival of streaming service TV + this autumn. Apple had already announced that app for macOS.
Apple has not responded to the rumor. The manufacturer usually announces new versions of its operating systems at its own developer conference WWDC. It will take place in early June.