I see lots of posts on here asking how to meet people in Cambridge.
I don't think the problem is finding people who have the same interests (in my experience anyway) because we have loads of pubs, gigs, online meet ups etc. Stuff gets posted in this subreddit all the time with ideas. For me the problem was not knowing how to actually start a conversation with a total stranger.
I'm socially very awkward, so this isn't coming from someone who's naturally good at it. But I think once you get past the initial anxiety of making a fool of yourself it can be quite simple.
Basically you've just got to be brave about it.
Imagine you're in the pub and you see someone wearing a Fontaines DC shirt (and that's a band you also like). You could say "Hi, sorry to bother you, I just wanted to say I love your shirt".
If they just say "thanks" then that's fine. Literally just leave it there. That's them saying they're not really very interested. This is fine and normal and you might feel a bit stupid for 5 minutes but that's all. You'll get over it and it feels less weird the more you try it over time.
But if they reply with something like "yeah I saw them in London last year" - they are inviting you to have a conversation and you can see where it goes. Maybe you'll make a new friend.
Sorry if this all sounds horribly obvious but maybe it could help.