Futo Detective is the ongoing sequel for Kamen Rider W. It is published in Weekly Big Comic Spirits.
The official Twitter account released images of the upcoming manga cover designs. The designer worked with staff to decide on the best image for the cover. They colored existing manga materials and discussed the results.
Please note that these are not the final cover artwork:
The first manga volume is scheduled to be released on Spring 2018 and Volume 2 in Spring 2019.
Article Sources: Twitter