A new episode of Telltale's The Walking Dead series entitled 400 Days is coming to Vita this August.
It may be on other platforms too, but the announcement was made at tonight's Sony E3 press conference, so the Vita was the only platforms mentioned so far. We'll update if we find out more.
Additionally, Sony announced a new The Walking Dead bundle in August that would include all of Season One, 400 Days, and other, unannounced bonuses.
Season 2 is still expected out this autumn.