From 1950-1990, The US and Russia engaged in what is commonly known as The Cold War, primarily fought via proxy states rather than in an all out war. This included funding rebels, donating weapons and even sometimes interventions into foreign countries to puruse their own agenda. Countries that were caught between this style of warfare included many countries in the Middle East, Africa and Asia. Some examples include Vietnam, Afghanistan, Lebanon, Congo and Yemen.
While some countries have recovered thanks to regional blocs, most are still developing states rife with conflict and poverty. Many of the parties from those proxy wars are still either engaged in combat or are holding out a very high tension peace, which some countries have relapsed from, like Sudan.