TLR9 and lung cancer: For example, the TLR9 agonist PF-3512676 in combination with chemotherapy regimens (paclitaxel/carboplatin or gemcitabine/cisplatin) showed limited efficacy in improving overall survival in lung cancer patients, accompanied by risks of immune exhaustion, highlighting the hazards of excessive or non-specific TLR activation (no. NCT00254891) (227, 228).