What is immunotherapy primarily focused on?

Immunotherapy is primarily focused on using drugs to enhance the immune response. This therapeutic strategy leverages and strengthens the body's natural defenses to battle diseases, such as cancer, by stimulating the immune system or augmenting its components. The goal is to assist the immune system in recognizing and effectively attacking abnormal cells, such as cancer cells, or pathogens.

In contrast, the other options do not align with the core concept of immunotherapy. Using antibiotics to fight infections pertains specifically to antimicrobial therapy rather than enhancing immune function. Replacing vaccines relates to immunization practices but does not directly involve improving the immune response, and neutralizing toxins focuses on detoxifying substances rather than bolstering immunity. Thus, the essence of immunotherapy lies in its ability to boost the immune system's capabilities, making the correct answer focused specifically on this enhancement aspect.