SIRPA and primary central nervous system lymphoma: Alongside this, treatment with this combination not only had a direct cytotoxic effect in malignant cells but also favored an anti-tumoral innate immune response by shifting polarization of tumor-infiltrating macrophages toward inflammatory M1 and diminishing PD-1 and SIRPα expression in the remaining tumor-promoting M2 macrophages, highlighting the pathogenic role of the innate immune microenvironment in PCNSL.