A Kaby Lake refresh for the MacBook Pro line could occur this year. Information in the MacOS Sierra 10.12.4 beta “plist” might point to the existence of the new models. If the interpretation of that data is accurate, the new MacBook Pro models could be available sometime after that MacOS version launches.
Based on an earlier report, these MacBook Pros could enter production around July 2017. One of the 15-inch units will boost the maximum RAM to 32 GB, up from the current 16 GB.
It’s possible we could learn more about these machines at WWDC.