I have received a credit card in someone else's name with my address on it

This is most likely a person that has lived here before. I have moved in 3 years ago and I am still getting letters in their name. Initially I was writing 'RTS' on them and dropping them in the nearest postbox. Then I got bored of doing this and started throwing them away. With the latest one that I have received, curiosity got the better of me and I have opened it, as I felt a card inside. As I suspected, this is a credit card (most likely renewal) that was sent to my address, in someone else's name. What is the best course of action?

I am aware that legally, I shouldn't have opened it as it was not in my name. On the other hand, I am worried that if this person doesn't make their monthly payments, my credit score might go down due to them being linked to this address. I thought about contacting the bank directly (I've only seen the name of the bank once I've opened the envelope). But again, I shouldn't have legally opened it. Thoughts?