What exactly is Marxism?
Below you will find an actual scholarly article on Marx. Wiki is fine for pop culture knowledge, but pretty lousy for scholarly understanding. In any case, it’s a bit misleading to ask if any countries use the Marxist approach. Marx never really advocated a whole approach to government, rather he outlined a social and economic structure that he thought was inevitable as a natural progression. Marx was trying to be descriptive, and it is later people that put advocacy for things like state socialism into his mouth. As it turns out, nobody’s socioeconomic structure has turned out EXACTLY like Marx predicted, though certain elements of it were present even in his own time and are now, more in some places than in others.