Mestizos have existed since the time when Spain controlled much of what is now Latin America. A mestizo was usually the son of a Spanish father and a Native American mother. Mestizos form the largest part of the population in some Latin American nations, a large minority of mestizos makes up most of the population in Mexico, which is the Spanish-speaking nation with the largest population in the world.
During the colonial era, many Native Americans were converted to Roman Catholicism and began using the Spanish language instead of their traditional one. This was because of the concept that existed in the Spanish colonies which gave more "value" to European people over Native Americans and Africans. Because of this, many Native Americans gained better social status by calling themselves "mestizos" instead of "indios."
Indo-Mestizo (also known as Cholo) is a Spanish term for a person who is around 3/4 Native American and 1/4 Caucasian ancestry and an unfortunate derogatory term used by the European cast system for racial discrimination against Original Native people https://en.wikipedia.org/wiki/Casta
Indo-Mestizos term is a racial slur used mostly to discriminate against Original Native people in Eastern and Southern Mexico, much of Northern Central America,in South American West Pacific Side Ecuador, Peru, Chile Colombia and Bolivia
Indo-Mestizos usually have more Native American traits, but may have a light pigmentation with completely Native American features, or a dark pigmenation with some obvious Caucasian features.