The political structure of the US is fairly unique in the world. Most countries have very different systems.
For example, both Japan and Great Britain have constitutional monarchies in which the monarchs are figureheads. These countries have no directly elected president the way that the US does. Instead, these countries have a parliamentary system in which there is no separation between the executive branch and the legislative branch.
Other countries, like France, have a system where there is both a president and a prime minister. These executive officers share power with the parliament but the prime minister is not (unlike in Britain) also a member of the legislative branch.
These are three countries whose political structures differ from that of the US.