Valve has confirmed that they are not showing anything at the upcoming E3 in June. Someone had posted an email that they had received from Gabe Newell concerning E3 sometime last week. Fans were expecting more news on Half-Life 3, but looks like not at E3.
Newell stated, “We are not announcing anything at E3 really. We are not announcing Half-Life 3, Portal 3, Left 4 Dead 3. We are going to be showing people stuff that they already know about (CS:Go, Dota 2, 10′ UI, …)”. Want proof?
Like the email stated, Valve is working closely on DOTA 2 and Counter-Strike : Global Defensive, both of which are in a closed beta mode.