Researchers reported early clinical signals that CAR-T therapy can induce meaningful remission in treatment-refractory, seropositive rheumatoid arthritis. In the COMPARE phase 1 study at Charité-Universitätsmedizin Berlin, all six enrolled patients saw marked reductions in disease activity, with three patients in sustained remission off medication during follow-up. On the solid-tumor side, separate preclinical work highlighted immune and microenvironment barriers that can limit therapy durability. A study in Nature Cancer described tumor-infiltrating regulatory T cells using metabolic programs to drive aging-related decline in NK cells, a mechanism that may help explain why checkpoint approaches can fail to establish long-term immune control. The combined findings point to an oncology-and-immunology pipeline increasingly focused on both engineered cell therapy and deeper immune-cell biology governing memory, persistence, and resistance.