LAG3 and neoplasm: These molecules, such as programmed cell death receptor‐1 (PD‐1), cytotoxic T lymphocyte‐associated molecule‐4 (CTLA‐4) or lymphocyte‐activation gene 3 (LAG‐3), are expressed by tumor‐infiltrating T lymphocytes and, upon interaction with cognate ligands expressed by tumor cells and microenvironment, restrain immune rejection of cancer.