In the last few years, integrated photonic and plasmonic devices based on resonant cavities have become key building blocks in new microsystems, instruments, and diagnostic tools for a wide range of biomedical applications including point‐of‐care (POC) diagnostics, new drug development, and proteomics. Several resonant label‐free photonic and plasmonic biosensors for early diagnosis and monitoring of a wide range of pathologies have attracted a remarkable research interest due to their characteristic features such as high resolution, small size, immunity to electromagnetic interferences, compatibility with the CMOS technology, and strong light–matter interaction. Moreover, recently, photonic, plasmonic, and hybrid photonic/plasmonic micro and nano‐cavities have experimentally demonstrated a great potential also for trapping at the nanoscale and the interest toward these devices in the field of healthcare is quickly rising. Here, the recent advances in the field of integrated photonic and plasmonic devices based on resonant cavities for label‐free biosensing and trapping at the nanoscale are critically reviewed, with a special emphasis on the specific applications of these devices such as diseases diagnostics and new drugs development. Here, the most relevant recent advances in the field of integrated photonicand plasmonic devices based on resonant cavities for label‐free biosensing and trapping at the nanoscale are reported, with a special emphasis on some very interesting specific applications of these devices such as disease diagnostics and new drugs development.