What did the serbs and ethnic albanians have in common prior to the 1980's?

Before the 1980's both the Serbs and Albanians were part of Yugoslavia, a country that existed for much of the 20th century.

In the 1960's the country was renamed as Socialist Federal Republic of Yugoslavia and to reflect the ethnic and lingual minorities in the country, the country would consist of 6 socialist republics named:

SR CroatiaSR Bosnia and HerzegovinaSR MacedoniaSR SerbiaSR SloveniaSR Montenegro

However, ethnic tensions grew and each of these republics fought for independence. By the 21st century, all of these are now independent countries.