Conventional allogeneic SCT balances high-dose conditioning therapy (CT) and GVL effects against GVHD, high TRM, but low relapse rates. RIC uses lower dose CT and relies heavily on GVL activity balanced against the potential for higher relapse rates and GVHD but lower direct TRM. The optimal balance occurs when the combination of CT and GVL outweighs the risk of relapse, GVHD and TRM. Illustration by A. Y. Chen.