The following link is a very common starting point for ChIP assays: https://www.abcam.com/protocols/cross-linking-chromatin-immunoprecipitation-x-chip-protocol I have used an optimized version of this for leukemia cells successfully (so they are more blast-like than monocytic, but the protocol should be fairly similar) I would start with this and try to optimize the different steps to get a final protocol. The biggest difference I see between my protocol and their's is that I use 1% formaldehyde instead of 0.75%. My recommendation is to pay special attention to optimization of the chromatin shearing step, which in my experience has been one of the most critical steps of the procedure.

Well received, thank you very much for your quick response. Best regards