Erik Wolpaw the writer for Half-life 2: Episode One and Two has returned to work for Valve. Wolpaw is also know for his work on Portal, Portal 2, and Left 4 Dead.
Wolpaw initially left Valve back in February 2017 to work on Psychonauts 2 for Double Fine Productions.
Marc Laidlaw, who wrote for Half-life and Half-life 2, and Jay Pinkerton, who wrote for Portal 2, also left Valve around the same time as Wolpaw for different reasons, but Pinkerton came back to Valve in July of 2018
The news of Wolpaw’a return to Valve came from a screenshot of an email sent by the President of Valve, Gabe Newell. According to Shack News, Wolpaw was credited for work on Artifact, Valve’s trading card game which released in November 2018. It is likely that Wolpaw has been back for a little while.
Half-life fans have been asking Valve for a 3rd game for years, and many fans had lost hope. But, with the return of a Half-life writer, some fans are still holding on to a little bit of hope.