Edit: just to clarify, the Neural Engine itself is not really "new":
> The A11 also includes dedicated neural network hardware that Apple calls a "Neural Engine". This neural network hardware can perform up to 600 billion operations per second and is used for Face ID, Animoji and other machine learning tasks.[9] The neural engine allows Apple to implement neural network and machine learning in a more energy-efficient manner than using either the main CPU or the GPU.[14][15] However, third party apps cannot use the Neural Engine, leading to similar neural network performance to older iPhones.
Source: https://en.wikipedia.org/wiki/Apple_A11#Neural_Engine