Please do read up more on how sharding could be applicable. Good resources to look into would be articles by Vitalik Buterin, danksharding, and those stuff. These are complex topics and I wouldn't be able to give you as thorough of an explanation. Feel free to cite and raise any issues afterwards.
Could you, please, define what is "blockchain sharding" based on those good resources? Could you answer the question of the topic starter:
If Data Sharding is already on the blockchain then how do we know that it is already implemented? Is there any example of such implementation to relieve the Blockchain Burden?