CTLA4 and anemia (phenotype): By blocking inhibitory signals to cytotoxic and helper T lymphocytes and suppressing Tregs activation (anti-CTLA-4) while blocking inhibitory signals to B lymphocytes, NK cells, and macrophages (anti-PD(L)-1), ICIs unleash T-lymphocyte/NK cytotoxicity and B-cell synthesis of autoantibodies, possibly leading to ICI-related cytopenias (anemia, thrombocytopenia, neutropenia or bone marrow failure) [33].