yes you can configure a port-channel if you are connecting the switch stack and other switch with multiple links, instead of spannig-tree blocking all ports expect one, it would be a good idea to use port-channel where we use all the bandwidth.
When configuring a port-channel across cross stack we cannot not use "PagP" protocol and it would be good to use "stack-mac persistent" command if you are using LACP protocol.
Here is a good link on configuring etherchannel on 3750 stack:
We are pleased to announce availability of Beta software for 16.6.3. 16.6.3 will be the second rebuild on the 16.6 release train targeted towards Catalyst 9500/9400/9300/3850/3650 switching platforms. We are looking for early feedback from custome...