Not much is known about the iPhone 6S which Apple is planned to reveal during its June 2015 keynote but according to Taiwanese Media we could see Apple implement some interesting technology into the new iPhone 6S.
The technology we are talking about is called Force Touch and is currently already available in the new Apple Watch. As Apple explains it, Force Touch uses tiny electrodes around the Retina display to distinguish between a light tap and a deep press, and trigger instant access to a range of contextually specific controls. This most likely also means that a ton of new gestures will be added in future iOS versions (maybe iOS 8.2?)
Other then that, Taiwanese Media also claims that the 6S will feature a dual lens camera capable of optical zoom, a new technology is also being used that allows for more light to reach the lens and with this increase the image quality.