Orthotopic and metastatic tumour models are increasingly recognized as essential tools in preclinical cancer research for understanding tumour biology and drug development. While subcutaneous tumour models are widely used in early drug discovery, orthotopic and metastatic models provide a more accurate representation of the tumour microenvironment and immune system, enhancing the predictive value of preclinical studies. These models use patient-derived tissues, organoids, and humanized mice to better mimic human disease and improve the success rate of anticancer drugs in clinical trials. Orthotopic models replicate the anatomical location of tumours, allowing for more clinically relevant assessments of drug efficacy and response. However, they are more complex to establish and maintain, requiring careful surgical procedures and monitoring. Metastatic models, which simulate the spread of cancer cells to distant sites, are crucial for studying metastasis and developing therapies targeting this process. Tumour organoid models, derived from patient tissues, offer advantages such as high establishment success rates and the ability to generate matched normal control tissues. Humanized mouse models, which incorporate human immune components, enable the study of immune system interactions in cancer therapy. Despite their benefits, challenges remain, including the need for standardized methods and the ethical considerations of animal use. Advances in imaging technologies, such as bioluminescence and non-invasive imaging, enhance the ability to monitor tumour growth and metastasis in these models. Overall, orthotopic and metastatic models are becoming increasingly important in preclinical research, offering a more accurate reflection of human disease and improving the translation of preclinical findings into clinical applications.Orthotopic and metastatic tumour models are increasingly recognized as essential tools in preclinical cancer research for understanding tumour biology and drug development. While subcutaneous tumour models are widely used in early drug discovery, orthotopic and metastatic models provide a more accurate representation of the tumour microenvironment and immune system, enhancing the predictive value of preclinical studies. These models use patient-derived tissues, organoids, and humanized mice to better mimic human disease and improve the success rate of anticancer drugs in clinical trials. Orthotopic models replicate the anatomical location of tumours, allowing for more clinically relevant assessments of drug efficacy and response. However, they are more complex to establish and maintain, requiring careful surgical procedures and monitoring. Metastatic models, which simulate the spread of cancer cells to distant sites, are crucial for studying metastasis and developing therapies targeting this process. Tumour organoid models, derived from patient tissues, offer advantages such as high establishment success rates and the ability to generate matched normal control tissues. Humanized mouse models, which incorporate human immune components, enable the study of immune system interactions in cancer therapy. Despite their benefits, challenges remain, including the need for standardized methods and the ethical considerations of animal use. Advances in imaging technologies, such as bioluminescence and non-invasive imaging, enhance the ability to monitor tumour growth and metastasis in these models. Overall, orthotopic and metastatic models are becoming increasingly important in preclinical research, offering a more accurate reflection of human disease and improving the translation of preclinical findings into clinical applications.