None - Kakashi had Obito's/The Sages chakra and Black Zetsu unexpectedely attacked Madara.It's not like he was face to face fighting him.
Susano'o is developed through power and emotion,hence Sasuke's Susano'o having developed each time his hatred increased during the Kage summit arc.
Kakashi had The Sage's power and Obito's + his emotions were higher than ever since his close friend died and he was in the most important battle in history trying to save the world and protect his students - High emotions + Power = Susano'o development.
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