Tito-Stalin split doesn't occur,Greek communists still lose civil war, Macedonian ones are able to hold to Greek/Aegean Macedonia with SFRY support,Greek population expelled, union of Aegean Macedonia with Vardar Macedonia within Yugoslavia, Stalin fearing that Yugoslavia grows to powerfull orders impeccably Stalinist Albania and Bulgaria to federate with Yugoslavia in order to put pressure on Tito not to split.
Balkan Socialist Federation is formed.Pirin Macedonia transfered to Macedonian SR forming Greater Macedonia of COMINTERN design, Western
Outlands transfered to Bulgaria.
It will probably last until Stalin's death ...