Ukraine ping
The Russians were extremely generous in their provision of both jet fighters and pilots to their North Korean ally. Literally dozens of Russian aces were created at the expense of many hundreds of US pilots.
https://en.wikipedia.org/wiki/List_of_Korean_War_flying_aces#Soviet_Union
https://www.smithsonianmag.com/smithsonian-institution/seventy-years-ago-soviet-mig-15s-attacked-american-pilots-180977440/
The Russian defense of Chinese supply lines likely led to the deaths of thousands of GI’s. That stubborn defense meant the Chinese were resupplied with food, equipment and ammunition, and the kinds of supply interdiction operations that literally starved Japanese forces during WWII were ineffective.
Yes. Russia has also obviously been supplying China, North Korea, Iran, Venezuela, Syria and other terrorist and communist nations with weapons and other military and government support for a long time.