If you were thinking that not linking the PAN and Aadhar will only make your PAN inoperative, that is only one of the consequences.

As notified in the notification dated February 13, 2020, CBDT specifically have mentioned that if the PAN and Aadhar is not linked, the PAN will become inoperative with effect from 01.04.2020.

Also, the person might be fined upto Rs. 10000 for failure to comply with the provisions and using inoperative/invalid PAN u/s 272B of the Income Tax Act. So, linking of PAN and Aadhar is mandatory to avoid penal actions and do valid financial transactions .