Clinical oncology is undergoing transformation from reliance on cytotoxic drugs to precision medicine and immunotherapy approaches anchored in molecular analysis of tumors at DNA, RNA, or protein level. Diversity of clinical tests based on molecular data (either single biomarker or high-dimensional “omics”), and frequent lack of rigor in development coupled with weak regulatory oversight of laboratory-developed tests, have led to confusion about which tests have similar clinical performance, or are reliable at all, for guiding cancer therapy decisions. NCI statisticians have had leading roles in several collaborative efforts to improve rigor and promote standardization of clinical tests in oncology. Highlighted examples of partnerships between industry, academia, advocacy groups, and government agencies include proliferation biomarker Ki67 sometimes used to assess need for chemotherapy in early stage breast cancer and tumor mutation burden for assessing likelihood of response to immunotherapy for several cancers. A checklist for assessing readiness of an omics-based test to be used clinically is recommended as a helpful reference to promote rigor in clinical test development.