CD4 and neoplasm: In subcutaneous tumor models of WT and TCRδ–/– mice, we quantified tumor-infiltrating T cell populations using flow cytometry and found that, compared with WT mice, TCRδ–/– mice exhibited substantially increased T cell infiltration, particularly CD3+CD4+IFNγ+ Th1 cells, in the TME following radiotherapy (Figure 3, K and L, and Supplemental Figure 6C).