The Steam Store page for Resident Evil Revelations 2 [official site] has listed offline co-op as a feature since preorders began and continues to do so at the time of writing. But the game, now released, doesn’t support local co-op and, according to a statement Capcom have made to VgG24/7, it probably never will.
The PC version of Resident Evil Revelations 2 supports a variety of customisable visual settings and resolutions. The decision to prioritise a single local screen was made to ensure a stable user experience across a variety of different PC settings and devices.
PCs have too many graphics to support splitscreen.