Deno as a "replacement for node" seems like a roughly accurate three word description. Neither Node nor Deno is a programming language. Both are
runtimes, just like the browser. All three of them link with V8 which is the actual runtime (technically it's a JIT compiler, and only Chromium based browsers use V8 -- Firefox uses SpiderMonkey and Safari uses WebKit).
So to answer the original question, "Does Deno work for frontend?", the premise of the question is inaccurate because Deno is an environment where you can run TypeScript code. It doesn't make sense to "run Deno in the frontend" (though maybe you could come up with some wasm monstrosity enabling an approximation of it). The better question would be, "can I share (as in re-use) TypeScript code in Deno and the Frontend?" to which the answer would be mostly yes -- but you'll still likely end up needing bundlers like webpack to help with it.