CD4 and neoplasm: Based on the results of the analysis of immunological blood parameters, triple therapy using RT+L19–IL2+anti-PD-L1 resulted in a significant increase of PD-1 expression on peripheral CD4+ T cells in the C51 tumor model at day 6 after the start of the triple therapy, while this expression decreased in the CT26 tumor model and remained unchanged in the LLC model (figure 3A).