Wha? I didn't know The Callisto Protocol had a season pass. As far as I can tell, only one part of it is story dlc, so might just wait for that to go on sale instead of spending $12 (Humble's discount) on the pass.
Tried out Halo Wars 2. It has some bugs like needing to turn off HDR to be able to see the missions after cutscenes and turning off foliage to avoid nasty flickering. The campaign was pretty fun, though (although not on the level of the Starcraft games). There are even still some online players...