Team and teem are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Team is a noun. It means a group congregated for a common task or purpose. Sports teams play ball. Teams within companies work on projects and handle problems.
Teem is a verb. It means to be abundant, in great supply or quantity. Teeming is the gerund form.
The following story uses both words correctly:
Tamika tried to join the corporate world, but realized two years in that she didn’t like it. The office politics. The antics involved in being “a team player.” So she left it all to join the Park Service. She found being in wide open spaces that teem with wild creatures was a much better fit for her personality.