At the outbreak of the Omega Virus there were two sorts of people, one kind was in for fighting and the other tried to hide under the bed. Sadly neither side survived the deadly attack that showed no mercy on the human flesh. Powerful people who though that they were secured, failed to protect the life of their families from the apocalypse.
Some went underground but they too were hunted down later by the zombies. Human race thought that it possessed the power to conquer the whole universe and now it cannot even protect its own self. All of it started in summer and the season is quickly changing which means that winter is approaching in its full bitterness soon. A secure place might just not be enough in severe climate; the humans who are present with Cade would need food supplies as well.
All the focus shifts to the food supplies because without it no one would see the next summer. As the troop moves forward the winter comes a lot earlier. Snowfall makes things terrible for the surviving little group which is short of food. In Warpath it was the zombies and then ghosts appeared in Ghosts now it is the weather, surely nothing is going in favor of the humans who are trying to survive.
Shawn Chesser has shifted the story here; there is no talk of fighting back now rather the humans are trying to survive. No aggressive narration by Adam Paul makes it clear that Cade has suspended the notion of fight for a while. May be in the spring or summer the survivors will comes out of their compounds with a new zeal.