@sky77, your answer is substantially inaccurate, because Electrum is a wallet that supports Trezor hardware generated keys.
However, @queeneleanor, Electrum is a Bitcoin only wallet. You can use the Trezor online wallet for Bitcoin, Bitcoin Cash, Ethereum and various ERC-20 tokens, which most of the ICO coins are. As long as you are using it with the Trezor, you are 99% safe.
This article goes into detail as well:
Why the $BCC Fork Will Cause a Short Squeeze in Bitcoin That Affects You
Ok great. I was wrong about Electrum compromising your private key. What's the value of using Electrum with Trezor? Where's the value beyond Trezor's own Bitcoin app? Also, ERC-20 token support is available in Trezor 1.5.0 firmware in conjunction with MyEtherWallet.