A Study of RC48-ADC in Advanced Melanoma Subjects With HER2 Variant (Mutation, Amplification, Overexpression)

Inclusion Criteria: * Voluntary agreement to provide written informed consent. * Male or female, Age ≥ 18 years. * Predicted survival ≥ 12 weeks. * Eastern Cooperative Oncology Group (ECOG) performance status score of 0 or 1. * All female subjects will be considered to be of child-bearing potential unless participants are postmenopausal, or have been sterilized surgically.Female subjects of child-bearing potential must agree to use two forms of highly effective contraception. Male subjects and their female partner who are of child-bearing potential must agree to use two forms of highly effective contraception. * Willing to adhere to the study visit schedule and the prohibitions and restrictions specified in this protocol. * Adequate organ function. * All subjects must be histologically confirmed, non-resectable stage III or metastatic melanoma, except for patients with uveal or ocular melanoma. * The subject has experienced disease progression or intolerance after receiving standard treatment in the past; Patients with disease progression within 6 months after receiving neoadjuvant or adjuvant chemotherapy regimens can be included in the clinical study. * The HER2 IHC test result is IHC 2+ or IHC 3+, the subject's previous test results (confirmed by the investigator) or the research center's test results are acceptable; the subject can provide the Specimen of primary or metastatic tumor for HER2 review/judgment. * According to the RECIST 1.1 standard, there is at least one m…