3D cancer models, including 3D cell cultures and organoids can be manipulated for preclinical drug discovery and in vitro model development. Generally, 3D cell cultures maintain several aspects of in vivo cell and tumor growth and have enabled drug developers to better bridge the gap between in vitro and in vivo studies. In 3D cell cultures, the tumor is dissociated into single-cell suspension and cultured in media as a monoculture or with other cell types. Tumor organoids, on the other hand, mimic organ organization and arise from adult, embryonic, or induced pluripotent stem cells, and are generally regarded as a complement to in vivo testing.