It's often said, either directly or through implication, that Russia and China are allies, and, together, are enemies of the West.
In fact, the actions of these two countries does show, not only antagonism towards 'western' countries, but a degree of cooperation between them.
Do not, however, mistake this for a solid long-term alliance. China and Russia both are playing the game of Realpolitik, and in that game, the two have some very different goals. Russia, and it's predecessor the Soviet Union, through it's actions, often showed it was not (at least, under most of it's leaders) looking for world domination. What the Soviet Union (and, especially leaders like Stalin) wanted was a massive world-spanning empire. They wanted to demarcate between "mine" and "not-mine" the same way European powers did in the late 1800s. While some Soviet leaders clearly were looking to expand the Soviet system across the globe, most, as seen by their actions, did not seem to want this.
The US, however, has (at least since WW2) always been looking for "world domination." They desire to be the banking hub, the cultural hub, and the political leader of the planet. Sure, some Presidents have focused on some of these while ignoring others, but in general, the US ideology has always been that "Our system is Freedom. Freedom is good. Therefore everyone should use our system."
Unlike Russia, China has been playing politics in this style as well. The problem with this - for Russia - is there will come a day when China wants things that harm Russia. The problem for Russia is that all signs indicate, when that day comes, China, not Russia, will get what it wants.
Russia still likes to think of itself the way the Soviets did, in that victorian mindset. Russians still view their country as a mighty empire, worthy of respect, and full of prestige. China is too busy with practical politics to bother with that nonsense. China effectively humors Russia, but that will not last.
We are starting to see the first signs of the split when it comes to the 2020 US Presidential election. China would benefit greatly from a pro-trade President, while Russia is simply happy with a weaker America, and if cutting US-China trade will make a weaker USA, Russia will support that.
I don't see Russia and China parting ways any time soon. Despite that, it will happen, likely within the next three decades. When it does, Russia will learn it's holding a far weaker hand of cards than it thought it did.