HPK1-IN-2 is a potent and selective inhibitor of hematopoietic progenitor kinase 1 (HPK1), which plays a key role in regulating T cell signaling in the immune system. By inhibiting HPK1, this compound enhances T cell activation and cytokine production, making it a valuable tool in cancer immunotherapy research. It is primarily used in preclinical studies to investigate immune checkpoint modulation and to develop novel therapies that boost anti-tumor immune responses. Its application extends to studies involving immune oncology, where restoring or enhancing T cell function is critical. HPK1-IN-2 serves as a pharmacological probe to validate HPK1 as a therapeutic target and supports the development of next-generation immune-modulating drugs.