What is the difference between a Renegade and Infidel? ?

A renegade is someone who rebels and leaves a group such as in  The New Order. 

Am infidel is someone who goes against any religion such as Kylo Ren did in SW 7.

The definition of renegade is disloyal or relates to leaving one group and joining another.

while

Infidel is A person who does not believe in a particular religion, esp. the prevailing religion.

A renegard is like a rebel or a person who goes against the established order or system whereas the second describes one who is unfaithful or not true.

ren·e·gade

/ˈrenəˌɡād/

noun

a person who deserts and betrays an organization, country, or set of principles.

"an agent who later turns out to be a renegade"

in·fi·del

/ˈinfədl,ˈinfəˌdel/

noun

a person who does not believe in religion or who adheres to a religion other than one's own.

"they wanted to secure the Holy Places from the infidel"

not faithful (infidel) might be a renegade, and a renegade might be not faithful, but renegade refers to running around out of control of others.  Infidel means a denier of a faith or belief, a blasphemer.  Completely different ideas, really.  A person could be neither, or both, or just one but not the other.  kind of like asking the difference between a person with blond hair and a person with blue eyes.  There is a commonality possible (the one is often also the other), but it is not required.

any online dictionary can help you

An infidel is generally someone whose religion is not that of the majority. In the contemporary world it specifically refers to someone who believes in a religion other than Islam and does not follow its code of conduct. A renegade is a general term for someone who who deserts (leaves) a religion, party or cause for another. In religious terms that would be "apostacy" if the person went public with their decision.

A renegade is the USA when they went to war against their King

an Infidel is anyone who does not believe in the Pagan allah

I am a Infidel but never been a renegade