Hi Karan,
HCI can pull data from other systems.
All the master data is in ECC and most of the Transaction data is in APO.
So, Master data from ECC can be pulled from LIS tables.
Also, for APO, most of the data is in Live cache. For example in DP module of APO. you have to take a backup of the infocube and get it pulled by HCI into S&OP.
Regards,
Sandeep