CMOS-integrated biosensors, generally referred to as CMOS biochips and their underlying technologies are discussed in this paper. These devices are used in biotechnology to precisely detect and study bio-molecular analytes from biological samples in a massively parallel fashion. While CMOS biochips offer cost-efficiency, scalability, ease-of-use, and robustness for biosensing applications, their growth and adoption has been limited in the past two decades. The rationale behind this shortcoming is discussed in this paper and possible solutions are presented.