In addition, to determine whether EGCG reverses the inhibitory effect of the PD-L1/PD-1 pathway on T cell activity, we conducted a co-culture experiment using F10-OVA mouse melanoma cells and tumor-specific CD3+ T cells isolated from the spleens of F10-OVA–immunized C57BL/6 mice. Here, PDCD1 is linked to neoplasm.