The Google Play Music app for Android has an update rolling out that brings new features to everyone. The bulk of the version 7.9 build is aimed at the future, namely Android O so a lot of the attention and focus of this release is to be found once O rolls out to everyone. That includes things like Notification Channels, a new feature that will be coming in Android v8.
For today however, there is a new Search History feature that you can access on devices today that will give you access to your music search history. This history includes any music, album or artist searches you have done either from the Play Music app or site.