In the absence of a validation cohort due to the relative scarcity of R/M HNSCC compared to other more common malignancies, such as NSCLC, coupled with the recency of first-line pembrolizumab approval, we employed internal cross-validation to improve the performance and accuracy of our CRP and NLR cut-off points in external cohorts. This evidence concerns the gene CRP and non-small cell lung carcinoma.