In this study, researchers are testing how well two drugs, Propranolol Hydrochloride and Pembrolizumab, work together to treat skin cancer called melanoma. Melanoma is a dangerous type of skin cancer that can spread to other parts of the body. The study focuses on patients with stage IIIC-IV melanoma that cannot be removed by surgery. Pembrolizumab is a medicine that helps the immune system fight cancer, while Propranolol Hydrochloride helps the body respond better to stress. Scientists want to find the best dose of Propranolol Hydrochloride and check for any side effects when both drugs are used together.

• The study will last up to 2 years with treatments every 3 weeks.
• Participants will receive treatment by mouth and through a drip (IV).
• There will be follow-up visits after finishing the study treatment.

Eligible participants must have specific medical conditions and agree not to become pregnant during the study. People with other serious health problems or who have had certain treatments before may not join. The researchers will carefully monitor all participants to make sure they stay safe during the study.