CD19 and neoplasm: No significant changes in the population of neutrophils (CD45+CD3‐CD11b+Ly6G+), B cells (CD45+CD3‐CD19+) or Tregs (CD45+CD3+CD4+FOXP3+) were observed in the tumor TME following anti‐MARCO treatment or its combination with PD‐1 mAbs (Figure S12G–I, Supporting Information).