וְרָאָ֧ה הַכֹּהֵ֛ן אֶת־הַבָּשָׂ֥ר הַחַ֖י וְטִמְּא֑וֹ הַבָּשָׂ֥ר הַחַ֛י טָמֵ֥א ה֖וּא צָרַ֥עַת הֽוּא׃
Examinará, pois, o sacerdote a carne viva, e declarará o homem imundo; a carne viva é imunda; é lepra.
Rashi on Leviticus
צרעת הוא IT IS A LEPROSY — that flesh is a leprosy; בשר is masc., and therefore the pronoun הוּא is used as its copula.
Chizkuni
צרעת הוא, “it is the affliction we have been discussing.” The reason why the Torah here uses the masculine pronoun is that it refers to בשר חי in verse 10 which is masculine.