The study will be divided into two stages: phase Ib and phase II. The safety and phase II recommended dose (RP2D) of Pexa-Vec combined with ZKAB001 in patients with local progression of failed first-line treatment or metastatic melanoma will be evaluated in phase Ib.~Objective response rate (ORR) and progression-free survival (PFS) of ZKAB001 combined with RP2D's Pexa-Vec or ZKAB001 monotherapy in patients with local progression or metastatic melanoma will be evaluated in phase II.~The study is also going to evaluate the combination therapy or monotherapy:~overall survival time ((OS)), disease control rate (DCR) and duration of remission (DOR) in patients with metastatic melanoma.~safety~the relationship between the expression of PD-L1 in tumor tissue and clinical effect；~the changes of immune microenvironment (CD8+ expression) in tumor tissue before and after Pexa-vec treatment.
The study will be divided into two stages: phase Ib and phase II. The safety and phase II recommended dose (RP2D) of Pexa-Vec combined with ZKAB001 in patients with local progression of failed first-line treatment or metastatic melanoma will be evaluated in phase Ib.~Objective response rate (ORR) and progression-free survival (PFS) of ZKAB001 combined with RP2D's Pexa-Vec or ZKAB001 monotherapy in patients with local progression or metastatic melanoma will be evaluated in phase II.