Engineered T cell receptors with built-in ICOS signaling (a co-stimulatory pathway) are reported to generate longer-lasting anti-tumor activity in adoptive cell therapy, according to research highlighted in the context of solid tumor durability challenges. The article frames the approach around a central failure mode for solid-tumor T-cell therapies: rapid loss of function or persistence in the tumor microenvironment. By integrating ICOS into the receptor design, the platform aims to sustain T-cell activity after tumor infiltration, addressing both exhaustion-like phenotypes and insufficient persistence. For development teams, the key relevance is whether engineered co-stimulation can translate into improved durability for solid tumor indications where conventional TCR and CAR strategies have struggled.