The rate of successful development of biomarker tests for early detection of individual cancers has been agonizingly slow, with the majority of cancers having no recommended screening test. Far too many patients are only diagnosed once symptoms become apparent, often by Stage 3 or 4, when prognosis is much poorer. There is hope for improvement, as promising results for a number of common and some less common types of cancer are making real progress. Some of these tests may complement or eventually replace current recommended screens, while for other cancers these tests would offer the only potential for early diagnosis. Focusing on a single type of cancer allows for obtaining biomarkers from different biosources (blood, urine, breath) and different biomarker classes. Single cancer assays may also benefit from more narrow training sets and likely smaller trials, reduced timelines, and lower cost for clinical validation compared to MCED validation. In some cases, these developments are intended to remain as single cancer assays, while others are more of a stepping-stone to multi-cancer early detection (MCED) efforts. At the same time the potential for individual cancer tests may be limited based on the timing and performance of MCEDs.