CD274 and neoplasm: Of note, pre-existing intratumoral T cells (ITCs, defined as sharing same clonotypes between pretreatment and post-treatment tumors) had a significantly larger fraction of clonotypes (44% versus 20%, P = 0.003) and clonal space (81% versus 45%, P = 0.003) in well responders (Fig. 5d), accompanied by higher expression of a signature related to tumor-reactive T cells (Extended Data Fig. 7b)26, indicating that pre-existing ITCs might be tumor-reactive T cells and neoadjuvant anti-PD-L1 therapy induced drastic clonal replacement in well responders.