Immunohistochemistry has become one of the most reliable techniques to study the expression of different molecules throughout very specific regions, especially in neuroscience. In this compilation, the authors begin by explaining how to perform excellent immunohistochemistry to obtain high quality images, and more importantly, how to automatically analyze these images. In immunohistochemistry, it is also essential to be able to guarantee analytical reproducibility. By involving experienced observers, data consistency may be improved by increasing interobserver concordance. Immunohistochemistry has value in melanoma diagnostics, allowing for the distinguishing of malignant melanocytes from benignant ones. This technique also has prognostic relevance in detecting tumor infiltrating lymphocytes and microvascular metastases, discerning the lymphatics from the blood vessels.