Samsung has released an update to the TouchWiz Home launcher, and the update takes the launcher to the one seen on Galaxy S8/S8+. The update makes it to version number 6.1.02, and it's the same version as Galaxy S8 launcher.
The Galaxy S8 launcher has various new features, and it's much faster than the previous TouchWiz launcher. The biggest change is the scrapping of app drawer icon, which can now be accessed by swiping up from the home screen.
Samsung did not release the update for all the countries, and it is currently available in the US and other European countries. You can grab it from the Play Store or sideload the APK by downloading it from apkmirror.com.
Also, make a note that the launcher works only with Samsung devices and that too devices running Android 7.0 Nougat only. If you've a Samsung Marshmallow device, then wait for the Android Nougat update.