To overcome the lack of therapeutic efficacy by either blocking MCP-1 or blocking CCR2 or CCR4 with pharmacological agents, we present a CRISPR/Cas9 double K/O in melanoma cells to target the activation of an alternative compensatory pathway activated by MCP-1 involved in MBM, such as MCP-1/CCR4. The gene discussed is CCR4; the disease is melanoma.