EXHIBIT 99.8

Joint Filing Agreement

In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the persons named below agree to the joint filing of a Statement on Schedule 13D (including any and all additional amendments thereto) with respect to the Class B Ordinary Shares of Gridsum Holding Inc. and further agree that this Joint Filing Agreement be included as an Exhibit thereto. In evidence thereof, the undersigned, being duly authorized, have executed this Joint Filing Agreement this 26^th day of October, 2020.

FutureX Innovation SPC (on behalf of and for
the account of New Technology Fund II SP as
one of its segregated portfolios)

By: /s/ ZHANG Qian                                               
Name: ZHANG Qian
Title: Director

FutureX Capital Limited

By: /s/ ZHANG Qian                                               
Name: ZHANG Qian
Title: Director

FutureX Fund Management (Hong Kong) Limited

By: /s/ ZHANG Qian                                               
Name: ZHANG Qian
Title: Director

FutureX Asset Management Limited

By: /s/ ZHANG Qian                                               
Name: ZHANG Qian
Title: Director

/s/ ZHANG Qian                                                                                       
ZHANG Qian

[Signature Page to Joint Filing Agreement – Gridsum Holding Inc.]