The phrase ‘son of man’ referring to Jesus occurs 85 times in the New Testament.
Jesus is the son of man on his mother’s side.
God promised Abraham a descendent in whom all nations of the earth would be blessed.
Genesis 22:18 And in thy seed shall all the nations of the earth be blessed; because thou hast obeyed my voice.
This seed is Christ
Galatians 3:16 Now to Abraham and his seed were the promises made. He saith not, And to seeds, as of many; but as of one, And to thy seed, which is Christ.
Christ is also the physical offspring of David
2 Samuel 7:12 And when thy days be fulfilled, and thou shalt sleep with thy fathers, I will set up thy seed after thee, which shall proceed out of thy bowels, and I will establish his kingdom.
Jesus was both son of man through his mother, and Son of God through his Father.
He was born with our nature and tempted exactly as we are.
Hebrews 2:17 Wherefore in all things it behoved him to be made like unto his brethren, that he might be a merciful and faithful high priest in things pertaining to God, to make reconciliation for the sins of the people.
The promise made to Moses:
Deuteronomy 18:18 I will raise them up a Prophet from among their brethren, like unto thee, and will put my words in his mouth; and he shall speak unto them all that I shall command him. 19 And it shall come to pass, that whosoever will not hearken unto my words which he shall speak in my name, I will require it of him.
Peter quotes this with reference to Christ.
Acts 3:22 For Moses truly said unto the fathers, A prophet shall the Lord your God raise up unto you of your brethren, like unto me; him shall ye hear in all things whatsoever he shall say unto you. 23 And it shall come to pass, that every soul, which will not hear that prophet, shall be destroyed from among the people.
Had Jesus not been the son of man, his sinless life and sacrifice would have been to no avail for the salvation of his fellow man.
1 Corinthians 15:45 And so it is written, The first man Adam was made a living soul; the last Adam was made a quickening spirit.
I hope you find this helpful.