Rumors such as this one are nothing special or new however, recent reports are suggesting that the game might actually be in development and will be released in 2018.
The main reason for this is the fact that 2018 will mark the 20th anniversary for the Half-Life series and fans are expecting something to be released that year. If it’s not the long-awaited third game in the series then there is hope that the original two games will be remastered.
It may not sound that promising on its own but when the HTC Vive was first revealed, the chairwoman announced that they were “co-operating with Half-Life” but the statement was quickly retracted. After this, Gabe Newell denied the existence of the game and stated they would only work on a classic game if the internal team was interested.
The potential release window for a new Half-Life game is shrinking, most of the original team are either retired or no longer work at Valve. If there is a new game in development, then it would be the perfect first title for Valve to officially release for the HTC Vive.
If there is a new game in development then fans should expect to see it by 2018 however there is no garaunteee it would even be “Half-Life 3”, a remastered original game is also a possibility.