Cancer continues to be a major global health issue causing millions of deaths annually. While traditional therapeutic methods may be effective in many cases, they may not be suitable for highly metastatic cancers. Moreover, the late detection of tumors, when they have already spread and are harder to treat, further exacerbates the challenge in managing this disease. As a result, there is a growing interest in developing complementary tissue‐engineered approaches for early cancer diagnosis and treatment to enhance patient recovery. Bioengineered cancer traps have gained significant attention due to their efficacy and ease of use. These trapping systems employ (bio)chemical and mechanical strategies to selectively capture and limit the spread of cancer cells, leading to their eradication from the body. Furthermore, when integrated into microfluidic devices, these cancer traps‐on‐a‐chip can be used for liquid biopsy and the early detection of circulating tumor cells and other tumor‐derived material, allowing for precision medicine treatments. Herein, this innovative approach to cancer theranostics, including its mechanism of action, current stage of development, and potential advantages and limitations is discussed.