Biomimetic membranes-camouflaged nanomedicines show promising potential in cancer therapy. Herein, we developed biomimetic hybrid membranes-camouflaged biosynthesized melanin nanoparticles, termed MBM-PM, by co-extruding near-infrared (NIR) light-absorbing melanin nanoparticles naturally enveloped in bacterial outer membranes (MBM) with programmed cell death protein 1 (PD-1)-expressing mammalian cell membrane nanovesicles (PM), for efficient cancer photothermal-immunotherapy. The melanin core within the outer membrane vesicles (OMV) generates a photothermal effect, inducing thermal stress to directly kill cancer cells and triggering immunogenic cell death (ICD), which enhances antitumor immunity. Furthermore, the pathogen-associated molecular patterns (PAMPs) present in the bacterial membrane component of MBMs stimulate a robust antitumor immune response. The PM components not only confer cancer cell-targeting capability but also block the PD-1/programmed death-ligand 1 (PD-L1) interaction, further enhancing immune activation. Our studies demonstrate that the MBM-PM nanoplatform can effectively eradicate primary tumors and significantly inhibit distant tumors and lung metastasis, offering a promising biosynthesized nanoplatform for cancer photothermal-immunotherapy.

Tumor heterogeneity has increasingly underscored the urgent need for personalized medicine, prompting the Food and Drug Administration (FDA) to approve in vitro companion diagnostics (CDx) for patient stratification. This evolving landscape has gradually transitioned towards imaging-based CDx, which is now further integrated with therapeutic modalities, culminating in the emergence of companion theranostics (CTx). In this review, we systematically elucidate the development of CTx and provide the first formal definition of this concept, thereby establishing a clear framework that distinguishes it from existing diagnostic approaches. We particularly emphasize the design principles underlying CTx by introducing activation strategies that leverage tumor active markers and treatment-activation mechanisms to enhance therapeutic precision. Finally, we address key challenges that remain, including the markers discovery, fine-tuning probes design, and regulatory approvals for clinical applications. We hope the insights shared in this review will contribute to the design of CTx for oncology, advancing personalized medicine.