Single-cell sequencing results showed that immune checkpoints such as programmed death-ligand 1 (PD-L1), cytotoxic T-lymphocyte-associated protein 4 (CTLA-4), and the T cell immunoglobulin and ITIM domain (TIGIT) are upregulated on the surface of tumor cells after TTFields intervention [28]. This evidence concerns the gene CTLA4 and neoplasm.