PDCD1 and non-small cell lung carcinoma: Another study in epithelial thymic carcinoma and NSCLC patients by Kim et al. [101] reported that a proliferative response of peripheral blood PD-1+CD8+ T cells, measured as the fold-change in the percentage of Ki-67+ cells, as early as one week after the start of ICI treatment, can predict clinical benefit in terms of PFS and OS.