TNFRSF4 and neoplasm: Notably, NK cells expressing CAR1 (CD8 TM‐CD3ζ SD), CAR2 (CD8 TM‐FcεRIγ SD), CAR3 (CD8 TM‐OX40 CD‐CD3ζ SD) and CAR4 (CD8 TM‐OX40 CD‐FcεRIγ SD) demonstrated effective anti‐tumour activity and prolonged survival in Nalm‐6 tumour xenograft animals, with CAR1‐NK cells showing the highest efficacy.