This is Hyliion's new hybrid system. It is an electric truck with a natural gas powered generator to charge the battery. It can run EV only for 25 miles to enter EV only areas in cities and cruise 1,300 mile on a tank.
This is a great idea for a realistic way to transition long-haul trucking to alternative fuels. Natural gas stations already exist and NG trucks have very low emissions. It is likely actually simpler than a modern diesel truck with all the emission controls and little fuel economy tweeks.
https://www.hyliion.com/erx-page/#/performance