Rookie Bo Johnson Mint retailer Condition

Product Name: Rookie Bo Johnson Mint retailer Condition
Belonged to my grandfather. I don't know alot about this item. So I'll be honest and tell you what I do know: it's in mint condition, it's inside this protective case thing you see in the picture which is the only part that's a little on the wear and tear retailer side, and that it's authentic. My grandfather was a collector like myself, I'm just not into cards. He has quite a collection but this one card is in mint condition where the others are not. I'm completely open to offers or information on how to sell this item.