No indication any are coming to GOG yet. All the quotes below come from the link to Telltale's twitter

August 08 2017 Batman: The Enemy Within
https://twitter.com/telltalegames/status/887718944353640449
"We're excited to announce that #Batman: The Enemy Within premieres August 8, with @TroyBakerVA returning as Bruce Wayne/Batman!"

In 2018:
The Walking Dead Season 4 (final season)
https://twitter.com/telltalegames/status/887722717255942144
"Play as Clementine in the fourth and final season of #TheWalkingDead: The Telltale Series, coming in 2018."

The Wolf Among Us Season 2
https://twitter.com/telltalegames/status/887726501872902145
"You asked for it, and here it is! #TheWolfAmongUs returns for a second season in 2018."

And I was so hoping for Tales from the Borderlands 2. I loved the first one. Still, it's probably good news... provided I'll like their Batman when I eventually get it.

The Wolf Among Us 2 is great news! Didn't think they would do a second season, especially after the comic series (Fables) ended some time ago.

I'm impressed that TWD Season 4 will be the final one. I really expected them to just keep it going indefinitely.

Just like the TV show that has pretty much overstayed its welcome already.

FINALLY! Wolf Among Us 2!

As for the Walking Dead...well, they completely ruined the series with season 3...so maybe they will make season 4 as good as the first two seasons :P