If the Pons-Fleischmann effect involves hydrogen or deuterium fusing with hydrogen or deuterium, that is an event that would release energy. Rossi is supposedly fusing hydrogen with nickel, an event that would consume energy.
What does the first have to do with the second?
The Ni-H experiments were started after the D-Pd experiments and reported the same kind of excess heat, falling under the Pons-Fleischmann effect. It was much more difficult to get results in Ni-H systems than D-Pd systems.
Here is a typical Ni-H paper:
Violante, V., et al. Analysis Of Ni-Hydride Thin Film After Surface Plasmons Generation By Laser Technique - ICCF10