I have a domain that has keyword iphone in its name. Can't I be an affilate of Apple and sell Iphone in that domain. Let me know what kind of trademark issues happens with it
No, you can't - unless you have express permission from Apple - which they aren't going to grant. You can't use a trademark in a domain name if the usage will infringe upon their classification - like selling Apple products or any other brand of phones or anything related to phones.