According to Rockstar Intel (via GameInformer) there are files hidden inside the companion app to Red Dead Redemption 2 that hints at a possible PC release. The files in question are actually a long list of parametres, where the following are the most interesting of the bunch:
PARAM_Oculus
PARAM_companionAutoConnectIpDurango
PARAM_companionAutoConnectIpOrbis
PARAM_companionAutoConnectIpPC
Now, this is extremely little to go on, but if you squint and wish real hard it can look like Rockstar is working on getting the game to PC-owners as well (which wouldn't surprise us as this game will likely head to next-gen at some point too). For now it's merely speculation, and if it turns out to be true, you'll probably have to wait a while. It took GTA V 19 months to arrive on PC, after all, let's hope the wait is shorter this time around.