The CACHE challenge will involve two cycles of predictions in order to give participants the opportunity to incorporate learnings from the first round into their designs. The timing and sequence of the proposed challenge round is shown in FIG. . Challenges will be staggered in order to avoid overwhelming the experimental hub. As part of each challenge, participants will be asked to make predictions from a small library constituting the combined list of predicted compounds contributed to the first cycle by all participants. Experimental testing of these compounds and then comparing with predictions will facilitate inter-algorithm benchmarking.