Two clinical trials uncovered that afatinib achieved better clinical improvements than erlotinib in lung squamous cell carcinoma (LUSC) [29] or methotrexate in head and neck squamous cell carcinoma (HNSCC) [30], illustrating afatinib’s outstanding clinical efficacy in tumors with wild-type EGFR. Here, EGFR is linked to squamous cell lung carcinoma.