I have noticed enrichment of specific sequence motif in intersection between two genetic elements.
I would like to know what enrichment analysis should I do (have checked previous posts, but haven't found anything about enrichment in intersection).

Example:
Genetic element A (for exmp. specific chromatin modification);
Genetic element B (for exmp. specific gene family promoter);
I have checked enrichment for motif in genetic elements A & B seperately- only slight fold enrichment compared to genomic background.
But when I look for motif in genetic elements A & B intersection - fold enrichment increases significantly.

What kind of correlation or other statistical test I should use here? How should I pick genomic background now?