Of note, the objective response rate was only 45% with pembrolizumab for non-small cell lung cancer, even in patients with high expression of PD-L1.126 In addition, a small proportion of patients experience hyperprogressive disease (HPD),127–130 which may be a result of regulatory T-cell (Treg) outgrowth and subsequent inhibition of antitumor immunity.30,131–133 These results suggest that PD-1 blockade needs to be prescribed in a personalized manner to maximize its efficacy. This evidence concerns the gene PDCD1 and non-small cell lung carcinoma.