STAT3 and cancer: CHRNA5 and CHRNA7 were found to be upregulated in lung cancer, with CHRNA5 mediating nicotine‐ and chronic stress–induced tumor progression, promoting cancer cell proliferation, migration, invasion, stemness, EMT, radio‐ and cisplatin resistance, and immune evasion, and CHRNA7 mediating nicotine‐induced PD‐L1 expression via the STAT3 pathway, collectively contributing to tumor progression, immune evasion, and poor patient survival [40, 41, 42, 43, 44].