PDCD1 and non-small cell lung carcinoma: As the above results indicated that the mere presence of CD8 + T cells was not entirely informative of whether advanced NSCLC patients were likely to respond to PD-1 blockade therapy, we next classified these patients into four groups based on the expression level of FAP and CD8 + T cell density: FAP low/CD8 low (n = 35), FAP low/CD8 high (n = 27), FAP high/CD8 low (n = 50) and FAP high/CD8 high (n = 23).