Ultimately, mercantilism was an economic policy that flourished in the Early Modern Era, before being overturned and displaced by capitalism. It was founded on the assumption that wealth was a limited resource, and thus understood trade as a zero sum game. Wealth acquired for one's own country was wealth denied to one's neighbors and rivals, and thus it was to the State's best interest to regulate its own trading and economic practices, maximizing exports and minimizing imports as a point of national policy.
Ultimately, one of capitalism's key insights was that wealth can be created through economic activity. Thus, many of the early capitalists called for reductions on the kinds of artificial market constraints which mercantilists imposed, arguing that such interference, rather than being to a country's benefit, actually served to hinder wealth creation.
With that in mind, you'll find very few countries today which follow mercantilism in its traditional form. Quite on the contrary, the current economic reality is one of globalization, where the world's various national economies are intertwined with one another, and businesses operate on an international scale. Look at a company such as McDonalds, to give one example, which operates chains in over one hundred different countries around the world.
However, if traditional mercantilism no longer seems to exist, I think you can point towards modern day successors with parallels to it, and draw on similar underlying mindsets. Consider, for example, how one of the effects of economic globalization has been an emigration of jobs out of the First World, as multinational companies have sought to reduce the cost of labor. This has resulted in the rise of a new brand of protectionist policies, aimed not at the creation of wealth but, rather, the protection of jobs. We saw this only recently with the election of Donald Trump and his rhetoric against free trade, and note that, while Trump was of the right wing, you can also find protectionist rhetoric from left wing politicians such as Bernie Sanders. If you were going to look for modern continuities with classical mercantilism, I think this is one place where you can search.