'True Tone Display' with its iPad Pro (9.7 inch version), stating the technology as the first of its kind in a tablet. This means the smaller iPad Pro's display comes with four ambient sensors that measure the ambient light in a room to adjust the brightness and colour temperature. Despite the clichéd coverage of Apple's latest supposed 'innovation' (e.g. here and here), this is similar to a feature Amazon introduced with its fourth generation Kindle Fire HDX.
'True Tone Display' is part of a broader strategy by manufacturers to ameliorate problems with light emitting displays. For example, Amazon, Google and Apple all introduced different features to change the colour tone of screens to counter problems with blue light emission. Overall, while these features are helpful, reflective tablet screens are not suitable for prolonged reading. There are alternative technologies (e.g. E-Ink, Plastic Logic, Electrowetting and Mirasol) but many are currently underdeveloped for more featured reading (e.g. colour and multimedia). Also, in the case of E-Ink, the options, from Amazon and Kobo, tend to be restricted to six inch displays.