The road relates the journey of a father and son in a world desolated by a nuclear holocaust. A world covered in ashes, in which most men have fallen into cannibalism, and "hope" seems a nonsense.
The book is very hard, depressing, although it leaves some space for hope, if you continue with the plot. The descriptions of violent actions or degradation are crude. When it comes to recommending the book to others, this crudeness is the first disadvantage to be considered.
Although after a first reading it may seem that the whole plot is ultimately based on trust in God and hope, a closer reading allows us to sense that McCarthy does not necessarily reach that perspective: man is able to resist anything by force of will or by solidarity. If there is a why, any how is resisted.