HAVCR2 and neoplasm: To permit more patients to benefit from immunotherapy, the focus has changed to targeting alternative novel immune checkpoints in the tumor microenvironment [7], such as lymphocyte activation gene-3 (LAG-3) [8], T cell immunoglobulin and mucin domain 3 (TIM-3) [9], V-domain immunoglobulin-containing suppressor of T-cell activation (VISTA) [10], and human endogenous retrovirus-H long terminal repeat-associating protein 2 (HHLA2) [11](Figure 1).