What is the name of the cell that finds invading pathogens?

Answer 1

Monocytes are large, spherical cells that make up 2 to 8% of circulating WBCs. Monocytes enter peripheral tissues to become tissue macrophages which can engulf large particles and pathogens.
They secrete substances that attract other immune system cells and fibroblasts to the injured area.

However you may mean neutrophils (polymorphonuclear leukocytes) make up 50 to 70 % of all circulating WBCs. Their cytoplasm is packed with pale granules containing lysosomal enzymes
and bacteria-killing compounds (hydrogen peroxide and superoxide anions).
Neutrophils are very active and are generally the first to attack bacteria at the site of an injury. While digesting pathogens, neutrophils release prostaglandins that affect local capillaries, and leukotrienes that attract other phagocytes. The breakdown of used neutrophils in an infected wound forms pus.