If participant's doctor thinks it can be safely performed, at Week 3 after starting dabrafenib/trametinib, participant will have a tumor biopsy to check how the study drugs are affecting participant's immune system cells and the way participant's genes are being expressed in response to the study drugs. If the location of the melanoma is not easily biopsied in the clinic, a doctor in interventional radiology may perform the biopsy outside the clinic at Week 3 instead. The type of biopsy participant has will depend on the location and size of the tumor.