It's become somewhat of a joke that Valve Software doesn't make games anymore. It's not necessarily true - Dota 2 launched in 2013 and Counter-Strike GO launched a year before that - but people have been waiting long enough for Half-Life 2: Episode Three or Half-Life 3 that it just feels right. In a Reddit AMA, Valve president and founder Gabe Newell confirmed that there are new projects coming from the developer in the future.
Those new projects are being built in Valve's Source 2 engine. Dota 2 was moved to the new engine in 2015, so it's a key part of Valve's future plans.
"We are continuing to use Source 2 as our primary game development environment," wrote Newell. "Aside from moving Dota 2 to the engine recently, we are are using it as the foundation of some unannounced products. We would like to have everyone working on games here at Valve to eventually be using the same engine. We also intend to continue to make the Source 2 engine work available to the broad developer community as we go, and to make it available free of charge."
When asked about more games in the shared Half-Life/Portal universe, Newell simply replied, "Yep." He also confirmed that the films set in that universe are still coming from Star Wars: The Force Awakens director J.J. Abrams.
What's not coming anytime soon seemingly is Half-Life 2: Episode Three or Half-Life 3. When asked about either potential sequel, Newell joked about it.
"The number 3 must not be said," he wrote.