I wouldn't have a problem with the mix of black and stainless steel.

Change your cabinet colors to a lighter shade. Like an off white, swap out your black refrigerator for a stainless still with black accents and everything should look great! Lighter cabinets will also make the kitchen feel bigger and brighter

Swap it out! Leave your warm wood cabinetry!

Since you have only 2 predominant colors in your kitchen (black & maple finish), I would not recommend inserting only one item of a stainless steel nature that has no relationship to anything else in the space.
My first recommendation would be to purchase a refrigerator with custom wood panels that would match your current cabinetry…they're not a whole lot more than conventional types.
If that's not a viable option, & you just have to have stainless, then I would incorporate a metallic backsplash that would provide a very important visual balance.
i.e. Penny tiles would look great in a gray/pewter tone!