Programmed death-1 (PD-1) and programmed death ligand-1 (PD-L1) are involved in the regulation of immune checkpoints and are closely related to the occurrence and development of tumors. In thyroid cancer, an increase in PD-L1 expression and an increase in PD-1 positive T cells may be predictive of higher invasiveness and a greater risk of recurrence. Anti-PD-1/PD-L1 therapy has had significant effects in many tumors, but the efficacy in thyroid cancer is still relatively limited, which also requires finding biomarkers those can better predict the efficacy. Further understanding of the mechanism of PD-1/PD-L1, the current research status in thyroid cancer, and biomarkers related to its efficacy may provide new treatment methods and ideas for patients with thyroid cancer.