This is a fear of strangers, or of unfamiliar people or cultures. It is a fear of the unknown, and can manifest itself in a variety of ways, such as avoidance of certain people or places, or even aggression towards those who are perceived as different. It can lead to discrimination,
From Wikipedia
Xenophobia is the fear or dislike of people who are perceived as being foreign or strange. It is an expression that is based on the perception that a conflict exists between an in-group and an out-group and it may manifest itself in suspicion of one group's activities by members of the other group, a desire to eliminate the presence of the group that is the target of suspicion, and fear of losing a national, ethnic, or racial identity.