Not true, Batman can’t find him on any database on earth, I doubt Fisk can find him, and reading Joker War recently, he stole Batman’s money, caused city wide chaos, escaped at the end, he also beat the designer who was gunning for Gotham’s rogues playing everyone.
I think Kingpin would have more then enough to deal with with the Joker
I still say Joker could beat him
Batman generally has to work for it to find Joker, and even then it's generally after Joker has spent some undeterminable amount of time setting up some sort of horribly dangerous plot and anounced it specifically to get Bat-sempai to notice him. The guy is basically a Batman-level planner who has chided R'as Al Ghul for his impatience.
Honestly, he and Joker probably mostly ignore once another unless Fisk gets close to killing Batman or Joker inadvertently messes with one of Fisk's plots. The aforementioned R'as Al Ghul might be a more direct threat to Kingpin.