NK-Exo expressed various NK receptors/markers, including CD56, CD69, cytotoxic receptors (e.g., NKG2D), NKp44, NKp46, NKp30, CD40L, PD-1, and molecules involved in tumor cell recognition and immune synapse formation (lymphocyte function-associated antigen 1 [LFA-1], DNAM1). Here, PDCD1 is linked to neoplasm.