你需要像这样为公司和用户建立一种关系
公司模型

public function user()
{
   return $this->belongsTo(Company::class,'user_id');
}

你的问题就会变成

response['appointMent'] = $this->appointment->where('user_id', Auth::guard('user')->user()->id)
                ->whereIn('status', array('Sched', 'Going', 'Request Appointment'))
                ->whereDate('set_date', '>', Carbon::now()->subDays(1))
                ->with(['company.user','applicant','job'])->get();

现在用户关系将在公司内部
或者反过来就是用户模型

public function company()
{
   return $this->hasOne(User::class); //Or hasMany depends on your needs
}

然后以下查询将更改为

response['appointMent'] = $this->appointment->where('user_id', Auth::guard('user')->user()->id)
                ->whereIn('status', array('Sched', 'Going', 'Request Appointment'))
                ->whereDate('set_date', '>', Carbon::now()->subDays(1))
                ->with(['user.company','applicant','job'])->get();