China-Russian alliance has been in the works since the US-led NATO war against Yugoslavia. The Clinton apologists like to claim that there was no downside to that war but always fail to mention that it was that war that pushed Russian and China into each others arms.
You are not quite correct. The intial thaw was during the late 1970s. Deng Xiao Ping built on that and architected the current Axis. The die was cast no later than 1987.