CCL21 and melanoma: Similarly, in melanoma, tumors with elevated VEGF-C levels were associated with increased intratumoral lymphatic vessels, attracting a greater influx of CCR7+ immune cells.47,48 In brain tumors, VEGF-C promoted the formation of lymphatic vessels and enhanced the effectiveness of anti-PD-1/CTLA-4 combination immunotherapy through the CCL21/CCR7 axis.49,50 Our pre-clinical research findings were in accord with recent studies, indicating that CCR7 in stromal cells enhanced the efficacy of anti-PD-1 immunotherapy combined with VEGF-C, providing an improved therapeutic strategy for HCC.