⁃ To be eligible for inclusion in this study, participants must:

• Be ≥ 18 years of age on the day of signing of informed consent.

• Have a life expectancy of at least 3 months.

• Have histologically or cytologically confirmed Stage 3 (unresectable) or Stage 4 metastatic melanoma per AJCC 8th ed. and be eligible for standard therapy with pembrolizumab.

• Have at least 1 lesion with measurable disease at Baseline by CT or MRI according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 by assessment of local site Investigator/radiologist.

• Have known BRAF V600 mutation status or consent to BRAF V600 mutation testing per local institutional standards during the screening period

• Have completed prior radiotherapy at least 2 weeks prior to study treatment administration.

• Have an ECOG Performance Status of 0 to 1.

• Have adequate organ and marrow function as defined by normal CBC, coagulation, serum chemistry and liver function tests on specimens collected within 10 days of treatment start.

• Have a negative serum pregnancy test within 72 hours prior to receiving the first dose of study medication (applies to women of childbearing potential \[WOCBP\]).

• Be willing to use either 2 adequate methods of contraception, 1 adequate method plus a hormonal method of contraception, or be willing to abstain from heterosexual activity throughout the study (Visit 1 to 120 days after the last dose of study therapy; applies to WOCBP who are not menopausal for \> 2 years, post-hysterectomy/oophorectomy, or surgically sterilized).

• Agree to use an approved adequate contraceptive method throughout the study (Visit 1 to 120 days after the last dose of study therapy; applies to sexually active male participants with a partner who is WOCBP).

• Be willing and able to provide written, informed consent for the study.