The teiru-form (polite: teimasu) of verbs o f motion, i.e., 行く (iku “to go”), 来る (kuru “to come”), 帰る (kaeru, “to return”), etc., expresses a somewhat special meaning.
1. 課長は出張に行っています （行く+ テイル形 + politeマス）
Kachō wa shuccho ni itteimasu.
Our chief is on a business trip.
2. 先生が私の家に来ています。（来る+ テイル形 + politeマス）
Sensei ga watashi no ie ni kiteimasu.
The teacher is here at my house.
In these sentences, can you tell where the chief and the teacher are located at the moment? Is the teacher now on the way, or is he/she already at my house?
Here, by using the moving verb in Teiru-form, some combined situation is stated:
Our chief went on a business trip. +The Chief is now in China.
(In English, it would correspond to the expression “Our chief has gone on a business trip.”)
The teacher came to my house. +Sensei is at my house now. So, strictly speaking, in example 2, it is unclear whether the teacher is on the way to my house or has already arrived and is in the house.
Some expressions can make it clear that the teacher is currently on the move:
2′. 先生は私の家に来ているところです（来る + テイル形 + ところ + politeです）
Sensei wa watashi no ie ni kiteiru tokorodesu.
The teacher is now coming to my house.
Adding ところだ （ところです） to the Teiru-form further clarifies the meaning of the present continuous tense.
Teiru-forms, when used with frequency phrases such as 毎日 mainichi/daily, よく yoku/often, いつも itsumo/always, indicate habitual behavior. (see also Habitual Action post.) Compare with the previous example 1 and 2.
1” うちの課長は毎週出張に行っている
Uchino kachō wa shuccho ni itteiru.
Our chief goes on a business trip (every week).
2” 先生は毎日私の家に来ています。
Sensei wa mainichi watashi no ie ni kiteimasu.
The teacher comes to my house every day.
These indicate habitual actions. There is no mention of whether the manager is on a business trip or whether the teacher is at my house at the moment.