To the Editor In a systematic review and meta-analysis, Lu and colleagues1 provided an overview of the most common tissue-based biomarker approaches for predicting response to anti–PD-1/PD-L1 (programmed cell death 1/programmed cell death 1 ligand 1) therapies and reported a higher diagnostic accuracy of multiplex immunohistochemistry/immunofluorescence compared with PD-L1 immunohistochemistry, tumor mutational burden, or gene expression profiling alone. However, we have 2 points of concern related to the methodological aspects of this systematic review and meta-analysis.