Multiculturalism exists today. In fact it is the dominant form of culture in America's major cities. Cities such as New York, Philadelphia, and Los Angeles have multiple ethnicities living all in one place. Places where there are only German-Americans or Mexican-Americans, for example are not multi-cultural, because there is only one culture among them. This happens, but it is somewhat rare.
Of course there is multiculturalism today. It was common place in the United States since its inception and even prior to, but now you see it in countries and regions where you wouldn't normally suspect it. Such as in the Scandinavian countries and in Eastern European Countries. South American nations too.
I believe there is still multiculturalism today. If anything, I would say it is more common in today's world than it has been in the past. More societies and communities interacting create multiculturalism. Since the world is becoming more globalized, it is easier to interact with others. This fuels multiculturalism.
As long as there continues to be different world cultures, there continues to be multiculturalism. Furthermore there is more multiculturalism today than in the past. Multiculturalism implies that there is a connection and appreciation between different cultures. In US history we may have had many immigrant cultures, but they were often secluded from each other and from society overall. Such as the Irish or Italian immigrants were initially. But today we see a stronger mix of immigrant cultures. Latino culture has become strong in the US, and people are generally very open about exploring its richness. Latino language, music and food is growing ever more popular in society, as they become introduced to American culture as well.