As one of the top global health problems, the effective treatment of cancer is one of the most urgent clinical challenges. Currently, the main treatments for cancer include surgery, chemotherapy, radiotherapy, and gene therapy etc. Chemotherapy is one of the most commonly used treatments, however it has limitations such as highly toxic side effects and low drug utilization rate that limit its application. Gene therapy, as an emerging cancer treatment, has limitations such as drug instability, off-target effects and low internalization efficiency. Poly(amino acid)s carriers with good biocompatibility, degradability and multifunctionality as drug carriers have received much attention, as they can reduce the toxic side effects of chemotherapy, improve drug utilization, and enhance the internalization efficiency and utilization of gene drugs. However, little attention has been paid to the nature of the carriers themselves. This paper reviews the immunomodulatory, anti-inflammatory, antioxidant, internalization-promoting and apoptosis-promoting functions of poly(amino acid)s drug carriers in tumor therapy to provide a theoretical basis for different carrier-drug-adapted synergistic therapies.