RUNX1 and severe combined immunodeficiency: To explore the function of Runx1 in MMT, we adoptively transferred BMDMs with siRNA‐mediated Runx1 knockdown (siRunx1‐BMDM, Figure S5, Supporting Information) or nonsense‐treated control (NC‐BMDM) or saline only (LLC control) together with LLC lung cancer cells (1:1 ratio) into macrophage malfunction nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice.