There has been rumours of multiplayer in The Witcher 3: Wild Hunt, but CD Projekt Red's Project Lead Konrad Tomaszkiewicz told Forbes that he "strongly feels that this final saga of Geralt has no place for meaningful multiplayer."
Furthermore there will be no DRM, which shouldn't come as a big surprise as CD Projekt subsidiary GOG.com has made a business out of selling DRM free games.
"DRM is the worst thing in the gaming industry. It's limiting our rights to play games owned by us. Let's imagine that you have a game that requires internet connection to prove that you actually bought it. What if you lose your connection because of your internet provider? You can't play anymore. It is worth mentioning that many people in Poland or even in the US and other countries still don't have an internet connection or have a very slow one. I was in such a situation once and I really didn't understand why I couldn't play games that I had bought. I believe that as long as people feel that companies are cheating them by selling games they cannot play freely, limiting their rights, and making unfair DRM, then they will fight against that."