In The Lancet Oncology, Bernardo Haddock Lobo Goulart and colleagues1 conducted a pooled analysis of correlations of overall response rate and progression-free survival with overall survival in trials of immune checkpoint inhibitors (ICIs) for metastatic non-small-cell lung cancer. The results showed that the correlations of overall response rate and progression-free survival with overall survival were generally moderate. Moreover, the authors focused on evaluating the correlation between PD-L1 expression (PD-L1 tumour proportion score <1%, 1–49%, and ≥50%) and prognosis, and found that the correlations ranged from weak to moderate when evaluating subgroups by PD-L1 expression.