In a jar or airtight container, combine the rolled oats, milk, cocoa powder, maple syrup, and vanilla extract.
Stir well until all ingredients are thoroughly combined.
Gently fold in the chopped cherries and dark chocolate chips.
Cover the jar or container with a lid and refrigerate overnight, or for at least 4 hours, to allow the oats to soften and the flavors to meld.
In the morning, give the oats a good stir and adjust the consistency with additional milk if desired.
Serve the Black Forest Overnight Oats cold or at room temperature, topped with additional cherries, cacao nibs, or chopped nuts for extra indulgence.