CpG ODNs, which are strong TLR9 agonists, induced tumor regression via the antitumor TLR9‐myeloid differentiation primary response 88 (MyD88) in a murine tumor model.12, 13, 14, 15 However, clinical trials have failed to demonstrate the utility of B‐CpG ODNs in patients with malignant tumors.16, 17, 18, 19 Hence, we focused on developing novel anticancer immunotherapies using A‐CpG ODNs. Here, TLR9 is linked to cancer.