FGL1 and neoplasm: Despite the early stage of tumor research, FGL1 is a new immune checkpoint molecule that is thought to have a promising future in clinical applications, especially in NSCLC immunotherapy [190–193], which is attributed to its overexpression in NSCLC cells and close correlations with immune regulation, tumor neovascularization [194], EMT progression [195], resistance and metastasis [116, 196, 197].