In the early 1980s, Coke realized an opportunity to form a strategic partnership with the Dr Pepper Company which exchanged use of superior Coca-Cola bottling facilities for a share in Dr Pepper sales profits. Only in regions of the country where Pepsi or 7up outbid Coke for this right did Coke resort to the production of Mr. PiBB.

https://beverage.fandom.com/wiki/Mr._Pibb

It entirely depends on where you live whether or not Coca-Cola distributes Dr. Pepper. There are still many areas where Mr. Pibb is not produced and Coke distributes Dr. Pepper.

So be careful when you buy it outside your local area. Check the label. You may find it is in fact bottled and distributed by the Coca-Cola Company.