Question

1 .It is definitely no mean task in marketing ( make it a retorical question) 2. I believe it will continue until we succeed ( future continue tense) ​

Answer 1

1 .It is definitely no mean task in marketing, is it? Or

It is definitely not a cake walk in marketing, is it?

2. I believe it will be continuing until we succeed  ​

Thanks for asking. Hope it helps.

Answer 2

1 . Does it really mean to task in marketing ?
2 . I believe it will be continuing until we succeed.