The cover to the first chapter of Whisper War has been held in secret. It features art by Arthur Adams, we know that much. Here is the preview of the variant cover for The Walking Dead #157
Granted, this is not final art for The Walking Dead #157, there could be some changes, but this is a good look at the way they are going. (probably just needs color but am loving if they go Black and white for it)
Click for a larger view
The Walking Dead #157 is out 8/3/16.