Testing CDM Predictions with Galaxy Cluster Gravitational Lensing In this talk, I will discuss how the predicted properties of dark-matter (DM) halos can be examined and tested using various effects of gravitational lensing, such as weak shear lensing, weak magnification lensing, strong lensing, the moving lens effect, and so on. I will also present recent results from applications of gravitational lensing to observations of galaxy clusters, the largest class of self-gravitating objects formed in the universe. Possible topics to be covered include the density of DM in quasi-equilibrium halos, the asphericity of DM halos, the splashback radius, and the recent discovery of the universal fundamental plane (FP) relation in cluster-size DM halos.