VSIR and neoplasm: With the deepening of the understanding of tumor immunity, the researchers found that in addition to established targets such as PD‐1, PD‐L1, CTLA‐4, new targets such as CD300ld,[77] discoid domain receptor tyrosine kinase 1 (DDR1),[78] and V‐domain immunoglobulin suppressor of T cell activation (VISTA)[79] also play an important role in tumor immunosuppression.