Take this with a grain of half-salt, because at this point it is only a half-rumor. This would be part of the reason for this interview. Geoff Keighley is also doing a documentary series called The Final Hours, in which he is looking into the development of Valve games like Half-Life, Half-Life 2, Portal, etc.
First caught by PC Gamer, a supposedly leaked transcript of an interview between the Game Awards’ Geoff Keighley and Valve’s Robin Walker mentions a game called Half-Life: Alyx. But apparently, there are rumors that Valve will be announcing a follow-up to Half-Life 2, just not the true blue sequel that fans have been dreaming about.