Hello and welcome to the forum. Thank you for your question. Please know that black spots on the gums are rarely indicative of cancer. Here is an article outlying other things that are much more likely. https://www.healthline.com/health/black-gums Oral cancer often has open sores rather than a black spot. We can get various types of moles and freckles in our mouth on our gums. I would guess it is more likely this type of thing. It's always best to have a doctor or in this case a dentist could do so as well take a look at it. Let us know.