Why is the word "cello" pronounced with CH /tʃ/ and not S?

Solution 1:

Cello comes from Italian where it's pronounced with /t͡ʃ/.

Concert comes from French where it's pronounced with /s/, concerto comes from Italian where it's pronounced with /t͡ʃ/.

According to Standford University Website, the letter c in Italian is pronounced /t͡ʃ/ when it's followed by i or e.
Examples:

• cello -> /ˈtʃɛləʊ/
• ciao -> /ˈt͡ʃao/
• concerto -> /kənˈtʃəːtəʊ/ etc.

As John Lawler says in a comment (with little changes):

Concert comes from French, and gets pronounced with /s/ like French. Concerto comes from Italian, and gets pronounced with /tʃ/ like Italian. As noted, English spelling doesn't represent English pronunciation. But French and Italian spellings do, and we borrowed the spellings as well as the pronunciations.

It seems to me that Italian words don't change their pronunciations in English. Other example include pizza, palazzo, cello, crescendo, zucchini, Pinocchio etc.