Repeat of 1936 Germany aiding Franco in Spain.
“The war provided combat experience with the latest technology for the German military. However, the intervention also posed the risk of escalating into a world war for which Hitler was not ready. He therefore limited his aid”
Putin is waiting for the right time to fully engage in war.
The russkies were also involved in the Spanish civil war, sending tanks and troops,as well as planes and pilots. More practice.