Firstly, we investigated the impact of KRAS/LKB1 co-mutations on survival outcomes in PD-1/PD-L1 inhibitor-treated lung adenocarcinoma patients from POPLAR and OAK trials and confirmed that KL subgroup had significantly shorter progression-free survival (PFS) compared with other KRAS-mutated patients (median PFS:1.3 vs. 4.1 months, p = 0.0025). The gene discussed is PDCD1; the disease is lung adenocarcinoma.