Harmonized biomarker assessments could improve diagnoses and the differential diagnoses of neurodegenerative diseases, enhance prognostication, allow monitoring disease progression, and improve stratification of participants for inclusion into clinical trials. Different contexts of use require diverse biomarkers that can facilitate disease staging, assess the severity of clinical symptoms, select participants for personalized therapeutic approaches, assist with differential diagnoses, monitor longitudinal progression and therapeutic response, and establish prognoses and meaningful outcomes. Biomarkers should always be integrated with cognitive, functional, and behavioral variables and can be used to measure and track downstream disease-modifying effects of investigational treatments. The combination of multiple biomarkers may offer the best strategy to be employed for patient selection and outcome assessments at present. Biomarkers for patient selection and outcome assessments in clinical and translational studies need to be homogenized; however, many challenges including access and cost issues, the presence of multiple simultaneous neuropathological phenomena, and limited access to many resources of biosample processing or advanced imagingImaging may hinder their applicability in different centers. This chapter explores the practicality of using neuroimaging and biofluid biomarkers for patient selection and outcome assessments in clinical and translational research, along with impactful geneticGenetics variants. It is expected that the issues to be discussed may leverage standard formats for the uniformity of biomarker use in different research settings.