There is a scenario in alternate history of a Russian victory in the Cold War. This was prevalent in the 1980s as 'future history', and was prevalent in the 1990s as the big 'what if' of the recent era, but we see it in recent alternate history as well. These scenarios never feel very realistic. The United States was older than the Soviet Union, it was much more stable, and had a stronger built in strength. Similar things could be said of the West in general. The Soviet Union collapsed under it's own weight. It realistic for Georgia to secede from the USSR in the 20th century. It's not realistic for the state of Georgia to secede from the USA in the 20th century. It is much harder to get the US economy to falter compared to the USSR. It is much harder to get the US to destabilize compared to the USSR. And in such a scenario, it's likely to assume that as bad as the US will be, the USSR will be worse.
Fiction will play with these issues. They may throw them out the window, and just have the USSR expand while the United States contracts, eventually overwhelming it and the world is suddenly Soviet. They may have the USSR win a nuclear war, despite the reality that both sides would decimate each other. They may have Superman win the Cold War. There are a few examples, but none are realistic and personally I think it was either America's to win or there was going to always be a tie.
Realistically, what if the Soviet Union won the Cold War? And is there any way that is realistic? Bonus points if you do not significantly alter the Second World War.