Melanoma is susceptible to immunotherapies and targeting it with both OVs and immune checkpoint inhibitors that were specifically designed to target this cancer and have previously been approved for clinical use was thought to have a better outcome, compared with monotherapies [182]. However, the **data** obtained from a phase II clinical study (NCT01740297) on patients with unresectable stage IIIB-IVM1c malignant melanoma suggests that pseudo-progression (a delayed tumour shrinkage following an increase in tumour burden after treatment) is common in immune checkpoint inhibitor therapies, T-VEC and T-VEC plus ipilimumab [183]. The lower pseudo-progression incidence was reported in checkpoint inhibitor monotherapy, and the duration response (DOR) was longer for patients without pseudo progression versus those with pseudo progression [183]. Furthermore, 39% of patients had an objective response and regression of visceral lesions was observed in 52% of patients [184].