גַּם־בְּנֵ֣י אָ֭דָם גַּם־בְּנֵי־אִ֑ישׁ יַ֝֗חַד עָשִׁ֥יר וְאֶבְיֽוֹן׃
귀천 빈부를 물론하고 다 들을지어다
Rashi
Both the sons of “adam” The sons of Abraham, who was called (Josh. 14:15): “the greatest man (האדם) among the giants”; the sons of Ishmael and the sons of Keturah.
Malbim
"Also", all groups of people, respected and not, rich and poor, everybody is ignorant about this.
Ibn Ezra
"Also" - calling the sons of Adam who aren't wealthy, or who are and are well known. That is the reason for also having "sons of man", to include the rich and the poor.
Rashi
and the sons of “ish” The sons of Noah, who was called (Gen. 6:9): “a righteous man (איש צדיק).”