The reason could be due to the presence of additional immune checkpoints, such as the lymphocyte activation gene 3 (LAG-3), T-cell immunoglobulin and mucin domain 3 (TIM-3), and T-cell immunoreceptor with Ig and ITIM domains (TIGIT), or lack of proper antigen presentation machinery in tumor cells [34]. This evidence concerns the gene HAVCR2 and neoplasm.