Shaytan is the devil whether from Jinns or humans. We read in Quran (Sura 6, Verse 112): And so, We have let for every Prophet, devils of Humans and Jinns, instigating one another with adorned talk by deception.
This means that there are devils frm Jinn and devils from humans.
Iblis is that Jinn who refused to prostrate to Adam and disobeyed Allah's order and cheated Adam and Eve.
Iblis is Shaytan but human devils are not Iblis, so, Shaytan is more general than Iblis.
May Allah (SWT) protect and save us all from every Shaytan.