KIR3DL3 and neoplasm: However, it has been shown that the KIR3DL3-HHLA2 pathway, which is considered an alternate immunosuppressive route to PD1, is implicated in tumor immune escape in various cancers, indicating that disrupting the KIR3DL3-HHLA2 pathway is a viable immunotherapeutic approach for treating cancer [136,147].