Flow cytometric analysis on day 35 revealed a reduced tumor burden within the spleen and bone marrow following FCRL5 CAR/IL-15 treatment (Fig. 6d), accompanied by an increase in TNF-α, IFN-γ, and IL-15 detected on days 28 and 35 (Supplementary Fig. S5a). Here, FCRL5 is linked to neoplasm.