Chess is a game with complete information - there are no accidents, we know the full history of moves at every step, we know all the moves that the other player can make.
Theoretically, we know that there is an equilibrium - it can be a theoretical draw or a win for one side (most likely white), but we cannot calculate it - we lack the resources.

Now a little bit about the best chess program.
In simple words, it consists of a position evaluation function based on general principles and specific factors (e.g., material ratio, king security, square control, doubled pawns are generally bad, rooks are best when they control free verticals, and bishops are bad when they rest on their own pawns, etc. etc.), the opening base developed by mankind to date, a table of endings for which the result is known, and a combination calculation engine based on an optimized Alpha-Beta cutoff.