UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
 Washington, D.C. 20549
SCHEDULE 13G
Under the Securities Exchange Act of 1934
Amendment No.: 0*
Name of Issuer: ZENDESK, INC.
Title of Class of Securities: Common Stock

CUSIP Number: 98936J101

Date of Event Which Requires Filing of this Statement: 12/31/2020

Check the appropriate box to designate the rule pursuant to which
this Schedule is filed.

[X] Rule 13d-1(b)
[ ] Rule 13d-1(c)
[ ] Rule 13d-1(d)

* The remainder of this cover page shall be filled out for a
reporting person's initial filing on this form with respect to the
subject class of securities, and for any subsequent amendment
containing information which would alter the disclosures provided in
a prior cover page.

The information required in the remainder of this cover page shall
not be deemed to be "filed" for the purpose of Section 18 of the
Securities Exchange Act of 1934 ("Act") or otherwise subject to the
liabilities of that section of the Act but shall be subject to all
other provisions of the Act (however, see the Notes).

CUSIP No.: 98936J101

1.  NAME OF REPORTING PERSON
    S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
    Janus Henderson Group plc
    EIN #00-0000000

2.  CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP
    a.   ___
    b.   ___

3.  SEC USE ONLY

4.  CITIZENSHIP OR PLACE OF ORGANIZATION
         Jersey, Channel Islands

NUMBER OF SHARES BENEFICIALLY OWNED BY EACH REPORTING PERSON WITH:

5.   SOLE VOTING POWER
     0**

6.   SHARED VOTING POWER
     6,962,600**

7.   SOLE DISPOSITIVE POWER
     0**

8.   SHARED DISPOSITIVE POWER
     6,962,600**

9.   AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
     6,962,600**

10.  CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN
SHARES
     Not applicable

11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (9)
    6.0%**

12. TYPE OF REPORTING PERSON
    IA, HC

** See Item 4 of this filing

Item 1.
    (a). Name of Issuer: ZENDESK, INC. ("Zendesk")

    (b). Address of Issuer's Principal Executive Offices:

         989 Market Street
         San Francisco, California 94103

Item 2.
    (a).-(c). Name, Principal Business Address, and Citizenship of
  Persons Filing:

         (1)  Janus Henderson Group plc
              201 Bishopsgate
              EC2M 3AE, United Kingdom
              Citizenship: Jersey, Channel Islands

    (d). Title of Class of Securities:  Common Stock

    (e). CUSIP Number:  98936J101

Item 3.

This statement is filed pursuant to Rule 13d-1 (b) or 13d-2(b) and
the person filing, Janus Henderson Group plc ("Janus Henderson") is a
parent holding company/control person in accordance with Section
240.13d-1(b)(ii)(G). See Item 4 for additional information.

Item 4.  Ownership

The information in items 1 and 5 through 11 on the cover page(s) on
Schedule 13G is hereby incorporated by reference.

Janus Henderson has an indirect 97% ownership stake in Intech
Investment Management LLC ("Intech") and a 100% ownership stake in
Janus Capital Management LLC ("JCM"), Perkins Investment Management
LLC ("Perkins"), Henderson Global Investors Limited ("HGIL") and
Janus Henderson Investors Australia Institutional Funds Management
Limited ("JHIAIFML"), (each an "Asset Manager" and collectively as
the "Asset Managers"). Due to the above ownership structure, holdings
for the Asset Managers are aggregated for purposes of this filing.
Each Asset Manager is an investment adviser registered or authorized
in its relevant jurisdiction and each furnishing investment advice to
various fund, individual and/or institutional clients (collectively
referred to herein as "Managed Portfolios").

As a result of its role as investment adviser or sub-adviser to the
Managed Portfolios, HGIL may be deemed to be the beneficial owner of
468,684 shares or 0.4% of the shares outstanding of Zendesk Common
Stock held by such Managed Portfolios. However, HGIL does not have
the right to receive any dividends from, or the proceeds from the
sale of, the securities held in the Managed Portfolios and disclaims
any ownership associated with such rights.

As a result of its role as investment adviser or sub-adviser to the
Managed Portfolios, Intech may be deemed to be the beneficial owner
of 14,221 shares or 0.0% of the shares outstanding of Zendesk Common
Stock held by such Managed Portfolios. However, Intech does not have
the right to receive any dividends from, or the proceeds from the
sale of, the securities held in the Managed Portfolios and disclaims
any ownership associated with such rights.

As a result of its role as investment adviser or sub-adviser to the
Managed Portfolios, JCM may be deemed to be the beneficial owner of
6,479,695 shares or 5.6% of the shares outstanding of Zendesk Common
Stock held by such Managed Portfolios. However, JCM does not have the
right to receive any dividends from, or the proceeds from the sale
of, the securities held in the Managed Portfolios and disclaims any
ownership associated with such rights.

Item 5.  Ownership of Five Percent or Less of a Class

Not applicable.

Item 6.  Ownership of More than Five Percent on Behalf of Another
Person

The Managed Portfolios, set forth in Item 4 above, have the right to
receive all dividends from, and the proceeds from the sale of, the
securities held in their respective accounts.

The interest of any one such person does not exceed 5% of the class
of securities.

These shares were acquired in the ordinary course of business, and
not with the purpose of changing or influencing control of the Issuer.

Item 7.  Identification and Classification of the Subsidiary Which
Acquired the Security Being Reported on by the Parent Holding Company

Intech, JCM, Perkins, HGIL and JHIAIFML are indirect subsidiaries of
Janus Henderson and are registered investment advisers furnishing
investment advice to Managed Portfolios.

Item 8.  Identification and Classification of Members of the Group

Not applicable.

Item 9.  Notice of Dissolution of Group

Not applicable.

Item 10. Certification

By signing below I certify that, to the best of my knowledge and
belief, the securities referred to above were acquired in the
ordinary course of business and were not acquired for the purpose of
and do not have the effect of changing or influencing the control of
the issuer of such securities and were not acquired in connection
with or as a participant in any transaction having such purposes or
effect.

SIGNATURES

After reasonable inquiry and to the best of my knowledge and belief,
I certify that the information set forth in this statement is true,
complete and correct.

JANUS HENDERSON GROUP PLC

By  /s/  Kristin Mariani
Kristin Mariani, Head of North America Compliance, CCO
Date 2/12/2021