PDCD1 and B-cell chronic lymphocytic leukemia: Coexpression of LAG-3 and PD-1 on tumor-infiltrating CD4+ and CD8+ T cells and the profound therapeutic effects of coblockers or the genetic deletion of LAG-3 and PD-1 have been observed in various model mice of tumors, including B16 melanoma, MC38 colon adenocarcinoma, Sa1N fibrosarcoma, IE9mp1 ovarian cancer (OC), Em-TCL1 CLL, and recurrent melanoma [75, 125–127].