This is a fairly traditional joke that has been around since I have been a youngster. Any time that someone decides it is the right time to wear camouflage, you identify what kind of clothing it is and ask them where that section of their body went.
Camouflage is so invisible that you cant see anyone who wears it. But this man is also wearing a high visibility vest that is common for city or county workers that are working on road projects that need to be seen.
This meme is funny but not very creative which will earn a 8/10.