Also, of interest, is that HP and Canon printers can use the same toner cartridges:
https://www.shop.xerox.com/supplies-accessories?brand=6346
For the most part, HP does not make its own printers anymore and just sells rebadged printers running their own firmware. It would not surprise me if the ink for HP Smart Tank printers is identical to the ink for Canon Mega Tank printers.
They reportedly are selling some models using technology that they obtained from Samsung, but aside from that, very little of what they sell they actually make. They are basically a middle man.