Launcher Icon is not Shown in Oreo 8.0/8.1
Yes, I also faced the same issue in Android Oreo.
1) Add your images by adding in Image Vector
This might not be the ideal solution. But deleting the directory named mipmap-anydpi-v26 will resolve the issue if you have correct icons in relevant folders.
I was having the same problem make sure you have set drawable or mipmap to icon attribute as well as roundIcon attribute under application tag in your Manifest file
<application android:icon="@drawable/ic_launcher" android:roundIcon="@mipmap/ic_launcher_round"></application>This might resolve someone's issue. Thanks.