Paladins and Smite will receive an update enabling the feature in “mid-to-late” January. When this happens, there will be a 24-hour downtime, but after that, voice chat, leaderboards, and gameplay will be supported on Xbox One, Switch, PC, and Mac.
“We are technically ready to support cross-play on other platforms as the opportunity arises,”
Source: N4G PC Crossplay Coming To Smite, Paladins and more Hi Rez Games