A 2015 report from the the International Agency for Research on Cancer provoked several lawsuits against Monsanto (now Bayer) after the agency found a link between the active ingredient in Roundup, glyphosate. A U.S. court is currently examining whether or not glyphosate cause non-Hodgkin's lymphoma and if Bayer-Monsanto knew of and tried to bury evidence of its carcinogenic product.

Link mentioned:
Of Mice, Monsanto and a Mysterious Tumor

Resources:
EPA Glyphosate Study
Monsanto and EPA work together to slow glyphosate study