Cancer nanomedicine, which uses nanotechnology to improve cancer treatment, has made significant progress but faces challenges in clinical translation. This review highlights the progress, challenges, and opportunities in cancer nanomedicine, emphasizing the need for better understanding of tumour biology and nano-bio interactions to develop more effective nanotherapeutics. Nanoparticles (NPs) are defined as particles in the 1–100 nm range, with unique properties that enable targeted drug delivery, improved therapeutic index, and enhanced drug release. Various NP platforms, such as liposomes, albumin-bound NPs, and polymeric micelles, have been approved for cancer treatment, while others are under clinical investigation. The EPR effect, which allows NPs to accumulate in tumours, is a key factor in NP delivery, but its effectiveness varies between patients and tumour types. Understanding the EPR effect and developing predictive markers for NP accumulation is crucial for improving nanotherapy outcomes. The review also discusses the challenges of NP–protein interactions, which can affect NP circulation, biodistribution, and toxicity. Strategies to enhance NP delivery, such as PEGylation and cell membrane coating, are explored. Additionally, the review highlights the importance of NP shape, size, and surface modification in enhancing tumour penetration and cellular uptake. The role of nanotechnology in cancer immunotherapy, including the development of theranostic NPs, is also discussed. The review concludes that further research is needed to optimize NP design, improve clinical translation, and develop personalized nanomedicines for cancer treatment.Cancer nanomedicine, which uses nanotechnology to improve cancer treatment, has made significant progress but faces challenges in clinical translation. This review highlights the progress, challenges, and opportunities in cancer nanomedicine, emphasizing the need for better understanding of tumour biology and nano-bio interactions to develop more effective nanotherapeutics. Nanoparticles (NPs) are defined as particles in the 1–100 nm range, with unique properties that enable targeted drug delivery, improved therapeutic index, and enhanced drug release. Various NP platforms, such as liposomes, albumin-bound NPs, and polymeric micelles, have been approved for cancer treatment, while others are under clinical investigation. The EPR effect, which allows NPs to accumulate in tumours, is a key factor in NP delivery, but its effectiveness varies between patients and tumour types. Understanding the EPR effect and developing predictive markers for NP accumulation is crucial for improving nanotherapy outcomes. The review also discusses the challenges of NP–protein interactions, which can affect NP circulation, biodistribution, and toxicity. Strategies to enhance NP delivery, such as PEGylation and cell membrane coating, are explored. Additionally, the review highlights the importance of NP shape, size, and surface modification in enhancing tumour penetration and cellular uptake. The role of nanotechnology in cancer immunotherapy, including the development of theranostic NPs, is also discussed. The review concludes that further research is needed to optimize NP design, improve clinical translation, and develop personalized nanomedicines for cancer treatment.