It can have one of several connotations, all related in some capacity to the title of Khan, which originated from the Mongol Empire and its subjects and was thereafter historically granted to Muslim rulers. Infiltration of the name from Central Asia into South Asia happened with the coming of the various Muslim Turks, Afghans, and Mughals into South Asia who used this name as a title as well as a suffix to indicate their ethnic identity
The communities that use the surname Khan include the Afghans, Turkic peoples in Central Asia and Northern Pakistan; tribes in Pakistan and their purported descendents in India and Bangladesh, Baloch tribes in Balochistan and in Sindh and various Mongol, Turks, and Tatar tribes in central and northern Asia
Khan is mainly used by the Pushtuns and in the South Asian Subcontinent a Pashtun is addressed as Khan Sahib routinely whether he has Khan formally as part of his name or not. Moreover, the term Khawanain is used to refer to the Khans, collectively, ...more

It can have one of several connotations, all related in some capacity to the title of Khan, which originated from the Mongol Empire and its subjects and was thereafter historically granted to Muslim rulers. Infiltration of the name from Central Asia into South Asia happened with the coming of the various Muslim Turks, Afghans, and Mughals into South Asia who used this name as a title as well as a suffix to indicate their ethnic identity

I came across many khans who usually belong to punjab or karachi but do not know pashto
if your name ends with khan then do u know why u have this surname , what is your family background, a pathan or else.