My fear is not the role these 'bots will play in World War III. That will be settled with nuclear weapons and biological warfare.
It is the role these robots will play in World War IV a year or so later, which will target civilians on the ground, not military strategic points. That role will be decisive.
Scavengers aboveground should get used to seeing and avoiding critters like these wherever possible.
If you know the history of warfare, you know as soon as a war breaks out that technology that was formerly a novelty or seemed to have potential (like mustard gas or the machine gun) instantly made quantum leaps forward in sophistication when opposing parties realised it might be the deciding factor in who was going to dominate the battlefield.
All that the Atlas model above needs is a railgun firing steel rods the size of a hair and a small atomic battery like the one in a pacemaker and it could run around the same grid sector killing people for decades without needing any reinforcements, support, replenishment or repairs. Compare that with a human soldier and it is obvious which one is cost-effective. An army of these beats an army of sloppy primates in uniforms with ease. In terms of artificial intelligence, how much do you think is really needed over and above simple terrain navigation? If it shows up on infrared with a heat trace, you shoot it. You could probably outsource the programming to interns in India and it would be pretty hard to get it wrong. I would know, I've done some drone sims for tenders and most of them were not as complicated as your average computer game.