According to recently rumors on CR, along with EF 85mm f/1.4L IS USM lens coming in this Summer. Canon is still working on the rumored Canon EF 24-70mm f/2.8L IS USM lens. The release date of this lens is currently unknown, could be announced in late 2017 to 2018. Previous development of this lens is not announced due to weight and size.
The EF 24-70mm f/2.8L IS lens is rumored for a long time. Previous rumors said that this lens will be announced in late 2015 to early 2016. Now according to CanonRumors, Canon is working on this lens, and the release date will be in next 18-24 months.
According to CR, there will be two new Canon 24-70mm lenses to be announced in 2014. One is a L-lens with IS version, the other is non-L lens with IS STM version. These two rumored lenses could be released in Mid or late 2014.