Dimers and use thereof

A dimer formed by two polypeptide chains, with each of said two polypeptide chains comprising an antibody Fc subunit, an immunoglobulin single variable domain (ISVD) specific for PD-L1, and an ISVD specific for CTLA4;

• wherein said ISVD specific for PD-L1 comprises a heavy chain CDR1, CDR2, and CDR3 comprising the amino acid sequences set forth in SEQ ID NOs:
• 3, 4, and 5, respectively;
• and
• wherein said ISVD specific for CTLA4 comprises a heavy chain CDR1, CDR2, and CDR3 comprising the amino acid sequences set forth in SEQ ID NOs:
• 17, 18, and 19, respectively;
• wherein the C-terminus of said ISVD specific for CTLA4 is fused to the N-terminus of the antibody Fc subunit via a linker;
• and
• wherein said dimer is a homodimer.