CD4 and neoplasm: Interestingly, mIF images from on-treatment tumor biopsies of two progressors with CD8 conversion (sarcoma [ID: 020] and prostate [ID: 023]) revealed an influx of CD8 T cells (>15%) while simultaneously lacking infiltration of B cells and CD4 T cells, or T cell co-expression of TCF-1 and PD-1 (Fig. 6 F).