They must contend with starvation, wildfires and earthquakes but also violent cannibals and thieves.
Papa says to "keep the flame alive" in not succumbing to barbarism and keeps a gun with two bullets one for each of them should it become necessary.
Sometimes Papa dreams of Boy's mother (Charlise Theron) and better times.
CW: grimdark barbarism including the aforementioned cannibals
In any top 10 lists of bleak movies this probably features, but I think that's a naïve reactive take.
Yes there is great misery here but its fundamental theme is of not succumbing to the basest of behaviour even when faced with terrible privation and grief.
There are also moments of light and as it nears the end, hope. It is in an odd way uplifting.
It's well cast, suitably ambiguous and uses dialogue to hint at things that just aren't there onscreen ("Why are you following us?") but matter.
Recommended, 8/10, ignore the reputation if you haven't seen it and give it a chance. It's not happy fun times, true but it's also not just wallowing in misery tourism.