Learn Italian: Che cosa guardano in televisione? - What are they watching on television?

In Italian, to ask 'what?', you can use che cosa (literally 'what thing'). You will also frequently hear people shorten this to just cosa or just che in everyday conversation. All three mean the same thing, but che cosa is the most traditional form.

Where is the word for 'they' in this sentence?

It is hidden in the verb! In Italian, you usually drop subject pronouns like loro (they) because the verb ending already tells you who is doing the action. The -ano ending on guardano clearly points to 'they'.

The English translation says 'are they watching', but isn't guardano just 'they watch'?

Italian often uses the simple present tense (guardano) for actions happening right now. While Italian does have a specific way to say 'are watching', using the simple present tense is perfectly natural and very common for both 'they watch' and 'they are watching'.

Why is it in televisione instead of 'on television'?

Languages often disagree on which little connecting words (prepositions) to use for media! In English we watch things 'on' television, but in Italian, you watch things 'in' television (in televisione). It is best to memorize this as a set phrase.