Hematopoietic progenitor kinase 1 (HPK1) is a serine/threonine kinase restricted to the hematopoietic compartment that plays a crucial role in cellular proliferation, apoptosis and modulation of the antitumor immune response. In mice, HPK1 deficiency is associated with enhanced immune response, and thus, HPK1 is considered a novel target for cancer immunotherapy.