As you can see, the guy in this photo is wearing the No. 99 with "Problems" written in the name section. Meanwhile, the lady is sporting the No. 1 with the message "I Aint" on her back.
The creation is undoubtedly in reference to the key line in the song which states, "I got 99 problems but a [sic] ain't one."
It's not the most innovative of custom-jersey designs as the song as been beaten to death over the years with various references. However, these two do deserve a round of applause for their effort for the wonderful jersey coordination and show of unity.
Via Big League Stew