CD4 and neoplasm: When first analyzed at day 7 post-initiation of bintrafusp alfa, equal numbers of both human CD4+ and CD8+ T cells were observed in tumors of control and bintrafusp alfa-treated mice; however, at day 21 and > day 28 post-initiation of bintrafusp alfa treatment, there were clear differences in CD4+ and CD8+ tumor-infiltrating lymphocytes (TILs) in bintrafusp alfa-treated mice vs. control.