Study of the Effectiveness and Safety of Acasunlimab Alone and With Pembrolizumab to Treat Advanced Melanoma of the Skin That Has Returned After Treatment With an Approved Checkpoint Inhibitor Therapy (ABBIL1TY MELANOMA-07)

Key Inclusion Criteria:

* Participants ≥ 18 years of age with histologically or cytologically confirmed diagnosis of relapsed/refractory, locally advanced unresectable (Stage IIIB, IIIC, or IIID) or metastatic (Stage IV) cutaneous melanoma, per American Joint Committee on Cancer (8th edition) staging.
* Participant must have radiographic progression based on RECIST v1.1 on or following ≥ 1 prior systemic therapy, according to local and international guidelines, including a programmed cell death protein 1 blocking antibody (anti-PD-1) treatment or combination treatment containing an anti-PD-1.
* Participant must have received a minimum of 2 cycles of an approved anti-PD-1 as monotherapy or a combination therapy containing an anti-PD-1.
* Neoadjuvant and/or adjuvant systemic therapy count as the first line of prior systemic therapy if there is documented disease progression ≤ 6 months after completion of therapy.
* Participants with a BRAF V600 mutation should have received prior BRAF-directed therapy (with or without a MEK inhibitor) prior to enrollment in the trial, unless deemed not clinically indicated by the Investigator due to concurrent medical condition or prior toxicity.
* Participant has an Eastern Cooperative Oncology Group performance status of 0 or 1 within 7 days prior to Cycle 1 Day 1.

Key Exclusion Criteria:

* Participants with non-cutaneous or acral melanoma.
* Participants with newly identified or known unstable or symptomatic central nervous system metastases or history of carcinomatous meningitis.

Note: Other protocol-defined Inclusion and Exclusion criteria may apply.