Rapid advancements in the understanding and manipulation of tumor-immune interactions have led to the approval of immune therapies for patients with non–small cell lung cancer. Certain immune checkpoint inhibitor therapies require the use of companion diagnostics, but methodologic variability has led to uncertainty around test selection and implementation in practice.


To develop evidence-based guideline recommendations for the testing of immunotherapy/immunomodulatory biomarkers, including programmed death ligand-1 (PD-L1) and tumor mutation burden (TMB), in patients with lung cancer.


The College of American Pathologists convened a panel of experts in non–small cell lung cancer and biomarker testing to develop evidence-based recommendations in accordance with the standards for trustworthy clinical practice guidelines established by the National Academy of Medicine. A systematic literature review was conducted to address 8 key questions. Using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) approach, recommendations were created from the available evidence, certainty of that evidence, and key judgments as defined in the GRADE Evidence to Decision framework.


Six recommendation statements were developed.


This guideline summarizes the current understanding and hurdles associated with the use of PD-L1 expression and TMB testing for immune checkpoint inhibitor therapy selection in patients with advanced non–small cell lung cancer and presents evidence-based recommendations for PD-L1 and TMB testing in the clinical setting.

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Author notes

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Cartun is now retired. Sholl and Furtado are the Guideline Expert Panel Co-chairs.

Competing Interests

Authors’ disclosures of potential conflicts of interest and author contributions are found in the Appendix at the end of this article.

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