Source: TW
There were no Scythians in India in 540-480 BCE. Not even in the frontier regions in North West in what is now Pakistan. Much less so in the heart of India where Buddha hailed from.
People pretend as if Indo-Scythians have some kind of an obscure history.
No, they are well documented in Indian sources. We know who is a Scythian and who is not.
The Buddha is not.
The first Indo-Scythian kingdom in India was established by King Maues (Greek) or Moga (Sanskrit). He did so by defeating the Greeks and displacing them in 98 BCE.
The last Indo-Scythian King was Rudrasimhan III, assassinated in battle against the Gupta Empire by the Gupta Emperor himself in 395 CE.