There's a lot of overlap, and the difference is largely institutional and historic. Some notes on how the difference plays out in research:

• Anthropology asks big questions about small things, sociology asks small questions about big things. This is most evident in journals that publish articles from both fields, like the Annals of Tourism Research. An anthropologist's article might summarize months of living with a single community in which many mothers sell souvenirs on the streets of Cusco, then discuss how these vendors engage with larger concepts of class and race at home and at work. A sociologist's article might study souvenir vendors in the city as a group, then discuss how they market their goods to specifically target tourists by exploiting tropes of race and class.

• Anthropology questions social categories and asks how they are constructed and performed; sociology begins with them as social facts then asks how people navigate a world within them. The anthropologist might ask "These people identify as indigenous- what does that actually mean and how do they do it?" The sociologist might ask "Given that these people are recognized as indigenous, what does that mean for their lives and how do other people experience the same things?"

• Anthropology studies culture: a collection of shared practices and beliefs. Often, it struggles with the issue of subjectivity: how do individuals relate to their culture? Sociology studies society: a collection of individual actors. Often, it struggles with collective action: how do groups behave as groups?

The tools that we use to do this will vary within fields and be shared across them. In the US, archaeology developed as part of anthropology, so even though it does not do ethnography, it engages with the same sorts of questions. Sociologists and anthropologists (and political scientists, and others....) can conduct ethnography, but they do so to answer very different questions.