According to Lenovo, there will be no new additions to the ultra high-end Legion Y900 series as priorities have shifted to the mainstream gaming segment instead. The more affordable Legion Y530, Y730, and Y7000 will all be launching in the July to September time frame. There is potential in a proper Y920 successor further down the line when the new Nvidia GPUs become available.
https://www.notebookcheck.net/Lenovo-has-no-plans-for-a-Legion-Y920-successor-for-now.308342.0.html