RecruitingDrug trialA Phase Ib/II Clinical Study of GH21 Capsules Combined With Osimertinib Mesylate Tablets in Patients With NSCLCThis study, including phase Ib , phase IIa and phase IIb, aims to evaluate the safety, tolerability, PK profile, efficacy and to determine the RP2D of GH21 capsules combined with Osimertinib mesylate tablets in NSCLC patients with EGFR mutations.