Humanized mice models are immune-deficient animals engrafted with human hematopoietic stem cells, genes, or tissues, serving as critical in-vivo surrogates for studying cancer, infectious disease, and autoimmune disorders. The global humanized mice model market size surpassed USD 310 million in 2025 and is projected to expand at a CAGR of ~9% through 2033, underpinned by a robust market forecast that reflects accelerating pre-clinical outsourcing, precision-medicine mandates, and record-level NIH/NCI funding for translatability initiatives. Synonymous demand for "human immune-system mice," "patient-derived xenograft platforms," and "next-generation hu-mouse kits" is converging into a high-growth niche within the broader industry expansion of humanized animal models.