https://www.techradar.com/news/moto-g6-is-a-mwc-2018-no-show-but-its-coming-soon

The recent leaks of the Moto G6, G6 Plus and the G6 Play led us to believe that Lenovo might unveil these new phones at MWC this year but all we got were some upgrades for the Yoga series. 

Lenovo did have a spot on a wall at their booth that was reserved for the next model of the G series. According to our sources, the G series is "coming soon", though it won't be revealed at MWC.