Conventional views regard malignant tumors simply as abnormal proliferations of somatic cells.However, cutting-edge evidence integrating genomics, proteomics, and immunology indicates that advanced tumors have transcended the realm of simple cellular aberrations, evolving into "neo-organs" with a high degree of histological complexity.Based on the theory of core functional acquisitions in cancer, this article systematically argues that tumors, driven by genomic instability, undergo phenotypic evolution, achieve metabolic reprogramming through the remodeling of protein interaction networks, establish immune evasion by actively sculpting the immune microenvironment, and seek neural contact and invasion to obtain proliferative signals.Tumors not only induce the alteration of surrounding cells to form a supportive stroma but also construct three-dimensional niches in a "cooperative cluster" manner.Building upon this theoretical framework, this paper further proposes forward-looking predictions: this "novel biological entity" will tend towards minimal functional structures in morphology, achieve metabolic autonomy and immune camouflage in its capabilities, and, under specific conditions, possess the potential to detach from the original host and form transmissible lineages.In essence, tumor evolution represents an attempt at "secondary organismal formation" by multicellular life within the host.