Nowadays, cancer become a global health problem and one of the greatest challenges in the medical field. Harmless therapy technique is urgently demanded. Immune check inhibitor aims at the reverse immune escape of tumor cell and awakens the defensive power of immune system to eliminate cancer. TIGIT is an immune inhibitory receptor of which binding signal suppress T cell action, expressed on T cells and natural killer cells. Interrupting interaction between TIGIT and its ligand allows T cells to recognize tumor cells again and be able to kill them. However, the mode of action of TIGIT blockade and the influence of post-translational modification (PTM) remains unclear. As a result, chemical synthesis of TIGIT with site-specific PTM is a pressing need to figure out TIGIT/ligand binding mode.