https://www.cnet.com/news/ipad-pro-2018-vs-ipad-pro-2017-vs-ipad-2018-heres-what-changed/

You'll also be able to charge your phone using the iPad's battery reserves, a feature within the USB-C standard. Notably, the iPad Pro for 2018 loses its headphone jack.

Editors' note: Updated most recently at 2:19 a.m. PT with more details.