Programmed cell death ligand 1 (PD-L1), inducing T cell exhaustion to facilitate immune escape of tumor cells, is upregulated by interleukin 6 (IL-6) in T cell lymphoma and ovarian cancer. The purpose of this study is to investigate the expression of IL-6 and PD-L1 in thyroid cancer, and whether IL-6 regulates PD-L1 expression.