。
A leopard cannot change its spots.
Literal
Leopard [topic-は] its spots [object-を] changing [cannot-ことはできない].
豹はその斑点を変えることはできない is a translation of the English proverb. 豹 (ひょう) means 'leopard,' 斑点 means 'spots.' The Japanese phrasing is a direct rendering rather than a native proverb.