It's possible that we can become invisible or camourflage as some parts of our body are transparent with the use of optical camouflage. It's just some sort of optical illusions that can be applied in real scene as it requires specific equipments used in the scene. Click on the pics below to watch how this optical camourflage really works. I believe one day that humans can become invisible as in the movie "Hollow Man".
Direct link to Optical Camourflage for more details.